1996-2006 Volkswagen LT Van Checkingpressuresonvehicles User Manual
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Checkingpressuresonvehicles for Your Volkswagen LT Van Second Generation (1996-2006)

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Vehicle Adapters re‐  
Adapters required for Miscella‐  
quired for refrig‐ refrigerant pipes to re‐ neous  
erant pipes to air ceiver  
conditioner com‐  
pressor and for  
air conditioner  
compressor itself  
tioner  
unit -  
N541-  
and in‐  
stall  
shut-off  
lk  
tap -  
VAS  
6338/4  
2- .  
Comply  
with  
notes  
⇒
pa  
ge  
121 .  
– If no  
shut-off  
tap -  
VAS  
6338/4  
2- is  
availa‐  
ble, a  
voltage  
of 12 V  
may be  
applied  
to shut-  
off  
valves -  
N541-  
and -  
N542-  
as an  
alterna‐  
tive.  
7. Clearing refrigerant circuit of contaminants  
117  
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Air conditioning system with refrigerant R134a - Edition 10.2014  
e-Golf 2014 and e-Golf 2014 with heat pump  
Vehicle Adapters re‐  
Adapters required for Miscella‐  
quired for refrig‐ refrigerant pipes to re‐ neous  
erant pipes to air ceiver  
conditioner com‐  
pressor and for  
air conditioner  
compressor itself  
e-Golf  
♦ Low-pres‐  
sure side  
adapter -  
VAS  
– Remove dryer car‐ – Install  
2014 ►  
tridge and seal re‐  
ceiver.  
adapter  
- VAS  
6338/3  
4- in  
6338/12-  
– After flushing, in‐  
stall a new dryer  
cartridge.  
place of  
expan‐  
sion  
♦ High-pres‐  
sure side  
adapter -  
valve  
(or a  
VAS 6338/3-  
drilled  
out ex‐  
pan‐  
♦ Purging elec‐  
trical air con‐  
ditioner com‐  
pressor,  
sion  
valve  
⇒
adapter -  
VAS  
pa  
6338/40- and  
Adapter -  
VAS  
lk  
ge 71 )  
– After  
6338/41- ,  
Observe  
purg‐  
ing, in‐  
stall a  
new ex‐  
pan‐  
notes:  
⇒ page 82  
sion  
valve.  
118  
Rep. gr.00 - Technical data  
lk  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Vehicle Adapters re‐  
Adapters required for Miscella‐  
quired for refrig‐ refrigerant pipes to re‐ neous  
erant pipes to air ceiver  
conditioner com‐  
pressor and for  
air conditioner  
compressor itself  
e-Golf  
2014 ►  
with  
♦ Low-pres‐  
sure side  
adapter -  
VAS  
– Remove reservoir – Start  
(dryer), and bridge  
refrigerant pipes.  
“Basic  
setting”  
in ⇒ Ve‐  
hicle di‐  
agnos‐  
tic test‐  
er, and  
start  
heat  
pump  
6338/12-  
– Join two adapters -  
VAS 6338/6- and  
connect to hose -  
VAS 6338/31- .  
♦ High-pres‐  
sure side  
adapter -  
VAS 6338/3-  
– After flushing, in‐  
stall a new reser‐  
voir.  
the  
func‐  
♦ Purging elec‐  
trical air con‐  
ditioner com‐  
pressor,  
tion  
“Charg  
e refrig‐  
erant  
adapter -  
VAS  
circuit”.  
♦ This will  
open  
6338/40- and  
Adapter -  
VAS  
the  
electri‐  
cal  
6338/41- ,  
Observe  
valves  
in the  
notes:  
⇒ page 82  
refrig‐  
erant  
circuit.  
♦ Leave  
vehicle  
diag‐  
nostic  
tester  
con‐  
nected  
to keep  
the  
valves  
open.  
7. Clearing refrigerant circuit of contaminants  
119  
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Air conditioning system with refrigerant R134a - Edition 10.2014  
Golf Hybrid 2014  
Vehicle Adapters re‐  
Adapters requirlked for Miscella‐  
quired for refrig‐ refrigerant pipes to re‐ neous  
erant pipes to air ceiver  
conditioner com‐  
pressor and for  
air conditioner  
compressor itself  
Golf Hy‐ ♦ Low-pres‐  
There are two versions ♦ Install  
brid  
sure side  
adapter -  
VAS  
of the fluid receiver:  
See vehicle specific re‐  
pair manual.  
adapter -  
2014 ►  
VAS  
6338/38-  
in place of  
expan‐  
6338/12-  
♦ Fluid receiver with  
permanently fitted  
dryer  
♦ High-pres‐  
sure side  
sion valve  
(or a dril‐  
led out ex‐  
pansion  
valve  
adapter -  
– Can be flushed  
through.  
VAS 6338/3-  
– After flushing, in‐  
stall a new receiver.  
♦ Receiver with des‐  
iccant bag or car‐  
tridge  
♦ Purging elec‐  
trical air con‐  
ditioner com‐  
pressor,  
⇒
page 71 )  
♦ Replace  
shut-off  
valves -  
N541-  
adapter -  
VAS  
– Remove desiccant  
bag/cartridge and  
seal fluid receiver.  
6338/40- and  
Adapter -  
VAS  
and -  
N542-  
6338/41- ,  
Observe  
– After purging, in‐  
stall a new desic‐  
cant bag/cartridge.  
with two  
shut-off  
taps -  
notes:  
⇒ page 82  
VAS  
6338/42- .  
Comply  
with notes  
⇒
page  
121 .  
♦ Remove  
restrictor  
in refriger‐  
ant line to  
heat ex‐  
changer  
for high-  
voltage  
battery,  
and drill it  
out (see  
notes be‐  
low)  
⇒
page  
121 .  
120  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
In the Golf Hybrid 2014, the refrigerant circuit is flushed in 2 cy‐  
cles. For the first cycle, the adapter for the shut-off valve -N541-  
is open, and the adapter for shut-off valve -N542- is closed. This  
will cause the refrigerant circuit with the evaporator in the heater  
and air conditioning unit to be flushed. For the second cycle, the  
lk  
adapter for the shut-off valve -N541- is closed, and the adapter  
for shut-off valve -N542- is open. This will cause the refrigerant  
circuit with the evaporator in the heat exchanger for high-voltage  
battery to be flushed ⇒ Heating, air conditioning; Rep. Gr. 87;  
Refrigerant circuit; System overview - refrigerant circuit (repair  
manual for the specific vehicle).  
Note  
♦ The illustration shows a refrigerant line -A- with a permanently  
installed restrictor -B- (without strainer). This refrigerant line  
must be drilled open with a suitable 5 mm drill bit (remove the  
restrictor if it is removable), and it must be cleaned before it is  
installed in the purging circuit. Renew the refrigerant line which  
has been drilled open after purging has been completed ⇒  
Electronic Parts Catalogue .  
♦ The diameter of the shown restrictor hole -B- is  
approx. 0.7 mm. Depending on the refrigerant line version, this  
restrictor is permanently installed or it can be removed. For the  
removable version a strainer may be fitted to prevent the re‐  
strictor hole from being blocked by suspended particles.  
7. Clearing refrigerant circuit of contaminants  
121  
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Air conditioning system with refrigerant R134a - Edition 10.2014  
8
Complaints  
8.1  
Possible complaints about refrigerant  
circuit  
Note  
lk  
♦ The air conditioning system is operating correctly if the air  
emerging from the vent on the dashboard is at a temperature  
o
of 7 C or less.  
♦ Set the Climatronic to: “LO”.  
♦ Set the air conditioning system: “AC” on; “max”; “cold”.  
8.1.1  
Test prerequisites:  
•
Self-diagnosis of the air conditioning system with the Vehicle  
diagnosis, testing and information system - VAS 5051A- using  
“Guided Fault Finding” cannot detect any faults; no switch-off  
conditions for the air conditioner compressor are set in the  
measured value block (only when the vehicle “air conditioning  
system” is fitted with self-diagnosis).  
⇒ Rep. gr. 87  
8.1.2  
Possible complaints  
Note  
For all complaints marked with a * ⇒ page 127 .  
♦ The cooling has failed completely. *  
♦ Insufficient cooling at all vehicle speeds and engine speeds.*  
♦ No cooling or insufficient cooling after a distance of several  
kilometres has been driven. *  
♦ The air conditioner compressor, the air conditioning system  
magnetic clutch - N25- or the air conditioner compressor reg‐  
ulating valve - N280- have been switched off by low-pressure  
switch for magnetic clutch - F73- , high-pressure switch for  
magnetic clutch - F118- , air conditioning system pressure  
switch - F129- or by operating and display unit for Climatronic  
air conditioning system - E87- or Climatronic control unit -  
J255- because pressure was too high or too low.* *  
♦ No fresh air flow, or very much reduced fresh air flow after  
driving some distance (evaporator iced up). *  
In addition the following complaints may also arise:  
The air conditioner compressor is noisy  
– Tighten the securing screws for the air conditioner compressor  
and the air conditioner compressor bracket using a torque  
wrench.  
– Check routing of refrigerant pipes; they must not touch other  
components and must be installed without tension (adjust if  
necessary).  
122  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Noises (refrigerant hammering) occur immediately after the air  
conditioning is switched on and/or in a curve or when the brakes  
are applied:  
– Discharge refrigerant circuit, evacuate and charge again (too  
much refrigerant in circuit).  
Note  
♦ Excess refrigerant oil in the circuit may also cause this problem  
(e.g. if the refrigerant oil level was not checked after the air  
lk  
conditioner compressor was renewed). In case of this com‐  
plaint, the refrigerant circuit must be purged with R134a re‐  
frigerant ⇒ page 67 .  
♦ The refrigerant must be drained from the air conditioning com‐  
pressor. To facilitate this process, turn the air conditioner  
compressor over by hand at the poly V-belt pulley or coupling  
disc of the magnetic coupling. Then fill refrigerant circuit with  
total amount of refrigerant oil (50 g direct into air conditioner  
compressor) according to ⇒ vehicle-specific workshop man‐  
ual .  
Water sprays out of the air vents (dash panel or footwell) although  
the air conditioning system otherwise works properly:  
– Check that the condensation water drain is properly routed; it  
must not be pinched or kinked.  
– The condensed water drain valve must not be hindered in its  
operation by wax or underbody sealant and must open and  
close properly.  
– Check the plenum chamber cover; it must be undamaged and  
be installed correctly (no water must flow into the evaporator).  
– Check water drains in plenum chamber; they must not be  
blocked (e.g. by leaves).  
8.2  
Smells from heater and air conditioner  
unit  
8.2.1  
Is the smell coming from evaporator or  
the heat exchanger?  
♦ Fishy smell  
– Due to leak in engine's cooling system or in heat exchanger of  
heater and air conditioner unit.  
Note  
If the fishy smell is weaker when the temperature is set to “cold”  
or stronger when the temperature is set to “warm”, check the heat  
exchanger for leaks.  
♦ Smell of a burnt clutch  
♦ Vapours from foot mats, retrospectively installed seat covers  
etc.  
♦ Putrid, mouldy smell  
– Due to accumulation of leaves, pine needles etc. in plenum  
chamber.  
8. Complaints  
123  
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Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
Clean plenum chamber.  
lk  
– Use water so that it cannot flow out of plenum chamber.  
Note  
Check water runoff points in plenum chamber.  
♦ Smell from heater and air conditioner unit  
Note  
Smells that can originate in heater and air conditioner unit can be  
detected in fresh air mode and in recirculation mode.  
– Due to too much condensation water in heater and air condi‐  
tioner unit  
Note  
Check the runoff points of condensation water ⇒ Rep. gr. 87 as  
indicated in the vehicle-specific repair manual.  
– Due to an old or very dirty dust and pollen filter  
Note  
Check the dust and pollen filter ⇒ Rep. gr. 80 as indicated in the  
vehicle-specific repair manual.  
– Due to deposits on the fins of the evaporator  
Note  
Clean the evaporator, using the ultrasonic air conditioner cleaning  
unit - VAS 6189A- ⇒ page 124 or the suction feed spray-gun -  
V.A.G 1538- and corresponding spray lance ⇒ page 125 .  
8.2.2  
Ultrasonic air conditioner cleaning unit -  
VAS 6189A-  
– The ultrasonic air conditioner cleaning unit - VAS 6189A- must  
be placed in the front-passenger footwell and sprays the agent  
Aero-Clean. Aero-Clean neutralises microbes and bacteria in  
the heater and air conditioner unit.  
The device is provided with instructions for use.  
Current equipment ⇒ ServiceNet; Workshop Equipment; Cata‐  
logue; Workshop equipment; Air conditioning/heating; Service  
equipment  
124  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
8.2.3  
Spraying the evaporator with the suction  
feed spray-gun - V.A.G 1538- and spray  
lance  
Spray the evaporator with Contra Sept directly using a spray  
lance (approx. 10 bar). Contra Sept neutralises microbes and  
bacteria directly at the evaporator.  
In order to enable access to the evaporator, some preliminary  
work and different spray lances are necessary, e.g. V.A.G 1538/5;  
V.A.G 1538/6 or V.A.G 1538/7.  
Vehicle-specific instructions for user are provided with the evap‐  
orator cleaning solution D 600 100 A2.  
Current equipment and spray lances ⇒ ServiceNet Function  
“Search”  
lk  
8. Complaints  
125  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
lk  
9
Connecting air conditioner service  
station  
9.1  
For vehicles that have connections on  
both low-pressure and high-pressure  
sides of refrigerant circuit  
9.1.1  
Connecting air conditioner service sta‐  
tion for measuring and checking  
– Switch off ignition.  
– Connect air conditioner service station to power supply.  
– Connect quick-release coupling adapters to charging hoses  
for air conditioner service station (handwheels not turned in‐  
wards, i.e. hand shut-off valves not open).  
– Switch on air conditioner service station and evacuate charg‐  
ing hoses (necessary only if there is air in the charging hoses).  
– Switch off air conditioner service station.  
– Unscrew sealing caps from service connections (with valve).  
– Connect air conditioner service station via service connections  
to the vehicle refrigerant circuit using quick-release coupling  
adapter.  
– Turn handwheel of quick-release coupling adapter inwards  
only far enough to ensure that valves on service connections  
are open (check using a pressure gauge; do not overstress  
valves).  
– Perform the intended measuring and checking work.  
126  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
10  
Checking pressures on vehicles  
10.1  
Checking pressures in refrigerant circuit  
(using air conditioner service station)  
lk  
Note  
♦ Check the cooling performance. The air conditioning system  
is operating correctly if the air emerging from the vent on the  
o
dashboard is at a temperature of 7 C or less.  
♦ Set the Climatronic to: “LO”.  
♦ Set the air conditioning system: “AC” on; “max”; “cold”.  
♦ Connections with valve and service connections for measuring  
and testing.  
10.1.1  
Test prerequisites  
•
•
•
Radiator and condenser must be clean (clean them if neces‐  
sary).  
The heat insulation on expansion valve is OK and properly  
installed. See vehicle-specific repair manual ⇒ Rep. gr. 87 .  
The poly V-belt is OK and properly tensioned. The V-belt for  
air conditioner compressor and alternator is in good condition  
and correctly tensioned. See vehicle-specific repair manual ⇒  
Rep. gr. 87  
•
•
All air ducts, covers and seals are OK and properly installed.  
Fault-finding on the electrical systems and vacuum system  
has found no faults. See vehicle-specific repair manual ⇒ Rep.  
gr. 87  
•
Self-diagnosis of the air conditioning system with the vehicle  
diagnosis, testing and information system - VAS 5051A- using  
“guided fault finding” cannot detect any faults; no switch-off  
conditions for the air conditioner compressor are set in the  
measured value block (only when the vehicle “air conditioning  
system” is fitted with self-diagnosis).  
•
•
The passage of air through the dust and pollen filter is not im‐  
paired by dirt. See vehicle-specific repair manual ⇒ Rep. gr.  
87  
The heater and air conditioner does not draw any secondary  
air at highest fresh air blower speed. The evaporator and heat‐  
ing do not draw any uncooled air at highest fresh air blower  
speed. See vehicle-specific repair manual ⇒ Rep. gr. 87  
•
•
The air duct flaps in the heater and air conditioner reach their  
stop positions. See vehicle-specific repair manual ⇒ Rep. gr.  
87  
The fresh air intake ducts under the bonnet and in the pas‐  
senger compartment and their water drain valves are in good  
condition. See vehicle-specific repair manual ⇒ Rep. gr. 87  
•
•
•
•
The engine is at operating temperature.  
The vehicle is not exposed to direct sunlight.  
The ambient temperature is higher than 15°C.  
All dash panel air vents are open.  
10. Checking pressures on vehicles  
127  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
•
With engine running and air conditioning set for maximum  
cooling output:  
⇒ Rep. gr. 87  
Setting maximum cooling output  
Settings on operating and display unit for Climatronic air condi‐  
tioning system - E87-  
– Select “Auto” mode (air conditioner compressor switched on).  
– Select temperature setting “LO” for driver and front passenger.  
Settings on heater controls:  
– A/C button and Rec or recirculate lbkuttons should be pressed.  
– Set rotary temperature switch to “Cold” stop.  
– Set rotary fresh air blower switch to “4”.  
•
The radiator fan(s) should be running radiator fan - V7- (at  
least at speed 1).*  
Note  
In some versions, the fan is not switched on until the pressure in  
the refrigerant circuit has exceeded a specified value.  
•
•
The fresh air blower - V2- should be running at maximum  
speed.  
The air flap for fresh air and air recirculation moves to the “re‐  
circulation” position or the air flow flap closes and the recircu‐  
lation flap opens (within 1 minute of starting the vehicle).  
•
•
The coolant shut-off valve is closed. *  
The valves for the pump valve unit are closed (and the coolant  
circulation pump is not pumping).*  
10.1.2  
Checking pressures  
– Switch off ignition.  
– Connecting air conditioner service station ⇒ page 126 .  
– Read pressure from pressure gauges; two results may be dis‐  
played.  
Ambient temperature (in de‐ Pressure in the refrigerant cir‐  
grees centigrade)  
+15℃  
cuit in bar positive pressure  
3.9  
4.7  
5.6  
6.7  
7.8  
9.1  
10.5  
+20 ℃  
+25℃  
+30 ℃  
+35℃  
+40 ℃  
+45℃  
128  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ The temperature of the components of the refrigerant circuit  
should be the same as the ambient temperature.  
♦ If individual components of the refrigerant circuit are warmer  
or colder, then the pressure will deviate from the values shown  
in the tables.  
♦ Absolute pressure means that 0 bar corresponds to an abso‐  
lute vacuum. The normal ambient pressure (positive pressure)  
corresponds to 1 bar absolute pressure. On most pressure  
gauges, a reading of 0 bar corresponds to an absolute pres‐  
sure of one bar (which is confirmed by the existence of - 1 bar  
marking beneath the 0 scale marking).  
♦ Where vehicles have a high-pressure sender - G65- which in‐  
dicates the measured pressure inltkhe measured values block,  
the measured pressure should agree with the values in the  
tables.  
⇒ Rep. gr. 87  
The pressure in the refrigerant circuit is lower than indicated in  
the table  
Insufficient refrigerant in circuit.  
– Check for leaks in the refrigerant circuit ⇒ page 58 .  
– Check the high-pressure safety valve.  
If the high-pressure safety valve has blown off:  
– Check activation of radiator fan.  
– Check refrigerant pipes and refrigerant hoses for restrictions  
in cross-section at bends that have too tight radius.  
– Check refrigerant pipes and refrigerant hoses for external  
damage.  
– If no defects are found, blow through refrigerant circuit with  
compressed air and nitrogen.  
The pressure in the refrigerant circuit is equal to or greater than  
that in the table  
– Start engine.  
– On vehicles with electrical air conditioner compressor, switch  
off ignition.  
WARNING  
High voltage on high-voltage system of hybrid vehicle. Danger  
of electric shock! Before starting work, carry out a visual check  
of high-voltage components in area of work. Comply with gen‐  
eral warnings ⇒ Hybrid electrical system; Rep. gr. 93 ; General  
warnings for working on the high-voltage onboard power sup‐  
ply system .  
– Set air conditioning system for maximum cooling output.  
10. Checking pressures on vehicles  
129  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
If the low-pressure switch had been removed in order to connect  
the air conditioner service station, bridge the electrical connec‐  
tions in the respective connector for pressure measurement.  
•
•
The air conditioner compressor is driven by the engine via the  
air conditioning system magnetic clutch - N25- .  
The air conditioner compressor regulating valve - N280- is ac‐  
tivated by the Climatronic control unit - J255- .  
⇒ Rep. gr. 87  
If the air conditioner compressor is not driven or the lrkegulating  
valve not activated when the engine is running:  
– Determine the cause, e.g. by reading the event memory for  
the air conditioning system, and rectify it.  
– Observe the test prerequisites.  
– Check power supply for air conditioning system magnetic  
clutch - N25- . If this is OK, repair magnetic clutch.  
– Check actuation of air conditioner compressor regulating valve  
- N280- .  
⇒ Rep. gr. 87 .  
10.1.3  
Continuation of checking pressures  
♦ Where vehicles have a restrictor and reservoir, check these  
(with internally regulated air conditioning system compressor)  
⇒ page 130 .  
♦ Where vehicles have an expansion valve and receiver, check  
these (with internally regulated air conditioner compressor)  
⇒ page 135 .  
♦ Where vehicles have an expansion valve and receiver, check  
these (without internally regulated air conditioner compressor)  
⇒ page 141 .  
♦ Where vehicles have a restrictor and reservoir and air condi‐  
tioning system compressor regulating valve - N280- (external‐  
ly regulated air conditioning system compressor)  
⇒ page 143 .  
10.2  
Checking systems with a restrictor and  
collector (with internally regulated air  
conditioner compressor)  
Note  
♦ Connecting air conditioner service station ⇒ page 126 .  
♦ Observe the test prerequisites ⇒ page 127 .  
– Raise engine speed to 2,000 rpm.  
– Observe air conditioner service station pressure gauge.  
130  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ Switch pressures for switches in refrigerant circuit are vehicle-  
specific.  
♦ The connection with a valve for the low-pressure switch or on  
the evaporator should only be used where the vehicle does  
not have a service connection on the low-pressure side and  
access to the connection on the air conditioner compressor or  
reservoir is not possible (measurement accuracy). This only  
applies to certain vehicles.  
⇒ Rep. gr. 87  
10.2.1  
Specifications:  
High-pressure side:  
Rising from starting pressure (when pressure gauge is connec‐  
ted) to maximum 20 bar.  
lk  
Low-pressure side:  
Falling from starting pressure (when pressure gauge is connec‐  
ted) to diagram value.  
A - High pressure (measured at the service connection) in bar  
positive pressure.  
B - Low pressure (measured at the connection with the valve at  
the air conditioner compressor or at the reservoir) in bar positive  
pressure.  
C - Permitted tolerance range.  
D - Low pressure (measured at the connection with the valve for  
the low-pressure switch or at the service connection) in bar pos‐  
itive pressure.  
E - Permitted tolerance range.  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
High pressure remains constant or in‐ Insufficient refrigerant in cir‐  
creases only slightly (above the pres‐ cuit.  
sure measured when the engine is  
– Look for leaks and rectify them.  
– Recharge refrigerant circuit.  
stopped),  
•
•
Low pressure falls quickly to the dia‐  
gram value or lower,  
The required cooling output is not de‐  
livered.  
•
•
High pressure is normal,  
Low pressure matches the diagram  
value,  
•
The required cooling output is not de‐  
livered.  
10. Checking pressures on vehicles  
131  
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Air conditioning system with refrigerant R134a - Edition 10.2014  
lk  
Possible deviation from specification  
High pressure is normal,  
Possible cause of fault  
Rectifying fault  
•
•
Low pressure is too low (see dia‐  
gram),  
•
The required cooling output is not de‐  
livered.  
Note  
If no fault can be found for this complaint, purge (clean) refrigerant  
circuit with refrigerant R134a ⇒ page 67 . If this is not possible in  
your workshop, blow through refrigerant circuit with compressed  
air and dry with nitrogen ⇒ page 65 .  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
High pressure increases only slightly The air conditioner compressor is de‐ – Purge (clean) refriger‐  
above the pressure measured when fective.  
the engine is stopped,  
ant circuit ⇒ page 67 .  
– Renew air conditioner  
compressor.  
•
•
Low pressure falls only slightly,  
The required cooling output is not  
delivered.  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
•
•
High pressure rises above specifica‐ Restriction or obstruction in the refrigerant – Feel the refrigerant  
tion,  
circuit.  
circuit with the hand  
to sense the tem‐  
perature gradient.  
Low pressure falls quickly to the di‐  
agram value or lower,  
•
At one component a  
temperature gradi‐  
ent will be detected:  
The required cooling output is not  
delivered.  
– If a hose or pipe is  
kinked or crushed,  
renew it.  
– In case of an ob‐  
struction, blow  
through refrigerant  
circuit with com‐  
pressed air and ni‐  
trogen.  
– Repeat the check; if  
the system does not  
operate correctly  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
132  
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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
•
•
•
High pressure and low pressure are Moisture in the refrigerant circuit.  
normal at first, but after a time,  
– Blow through refrig‐  
erant circuit with  
compressed air and  
nitrogen.  
The high pressure increases beyond  
lk  
the specified value,  
– Renew receiver.  
The low pressure falls to the diagram  
value or lower,  
– Repeat the check; if  
the system does not  
operate correctly  
The cooling power called for is not  
delivered.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Recharge refriger‐  
ant circuit.  
– Repeat check.  
•
•
High pressure is normal,  
The air conditioner compressor is defec‐ – Purge (clean) refrig‐  
tive.  
erant circuit  
⇒ page 67 .  
Low pressure is too low (see dia‐  
gram),  
– Renew air condi‐  
tioner compressor.  
•
The cooling power required is deliv‐  
ered.  
Note  
♦ If the fault is “high pressure normal, low pressure too low ”  
please note the following:  
♦ In this case, the evaporator may be iced up or the low-pressure  
switch for air conditioning system - F73- has switched off the  
air conditioning system compressor, although the correct  
quantity of refrigerant is present in the refrigerant circuit.  
10. Checking pressures on vehicles  
133  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation  
from specification  
Possible cause of fault  
Rectifying  
fault  
•
•
High pressure nor‐ Too much refrigerant in – Extract  
mal or too high,  
circuit.  
some re‐  
frigerant  
from the  
refriger‐  
ant cir‐  
cuit.  
Low pressure too  
high (see dia‐  
gram),  
•
The air conditioner  
compressor is  
noisy (especially  
immediately after  
being switched  
on),  
•
The  
quantity  
of refrig‐  
erant ex‐  
tracted is  
about  
•
The required cool‐  
ing output is not  
delivered.  
equal to  
the pre‐  
scribed  
charge  
quantity.  
– Renew  
the air  
condition‐  
er com‐  
pressor.  
•
The  
quantity  
of refrig‐  
erant ex‐  
tracted is  
signifi‐  
cantly  
lk  
greater  
than the  
prescri‐  
bed  
charge  
quantity.  
– Recharge  
refriger‐  
ant cir‐  
cuit.  
– Repeat  
check.  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
High-pressure and low-pressure Too much refrigerant oil in circuit.  
– Drain refrigerant cir‐  
cuit.  
are normal,  
•
The required cooling output is not  
delivered.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
•
•
High-pressure and low-pressure  
are normal,  
The air conditioner compressor is  
noisy (especially immediately af‐  
ter being switched on),  
•
The cooling power required is de‐  
livered.  
134  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ Overfilling with refrigerant oil can occur if the refrigerant oil  
level was not checked after the air conditioner compressor  
was renewed.  
♦ If the air conditioner compressor is not to be replaced, drain  
refrigerant oil from air conditioner compressor via the drain  
plug. From the total amount of refrigerant oil, fill 50 g direct into  
air conditioner compressor and fill remainder in refrigerant cir‐  
cuit according to ⇒ vehicle-specific workshop manual .  
10.3  
Checking systems with an expansion  
valve and reservoir (with internally regu‐  
lated air conditioner compressor)  
Note  
♦ Connecting air conditioner service station ⇒ page 126 .  
♦ Observe the test prerequisites ⇒ page 127 .  
– Raise engine speed to 2,000 rpm.  
– Observe manifold gauge.  
Note  
The switch pressures and the versions of switches in the refrig‐  
erant circuit are vehicle-specific.  
Pressures must be measured at the service connelcktions; the fit‐  
ting locations of these connections are vehicle-specific.  
⇒ Rep. gr. 87  
10.3.1  
Specifications:  
High-pressure side:  
Rising from starting pressure (when pressure gauge is connec‐  
ted) to maximum 20 bar.  
10. Checking pressures on vehicles  
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Air conditioning system with refrigerant R134a - Edition 10.2014  
Low-pressure side:  
Falling from starting pressure (when pressure gauge is connec‐  
ted) to diagram value.  
A - High pressure in bar positive pressure.  
B - Low pressure in bar positive pressure.  
C - Permitted tolerance range.  
lk  
136  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation  
from specification  
Possible cause of fault  
Rectifying  
fault  
•
High pressure re‐ Too little refrigerant in cir‐ – Extract  
mains constant or cuit or expansion valve  
some re‐  
frigerant  
from the  
refriger‐  
ant cir‐  
cuit.  
increases only  
defective.  
slightly (above the  
pressure meas‐  
ured when the en‐  
gine is stopped),  
•
•
Low pressure falls  
quickly to the dia‐  
gram value or low‐  
er,  
•
The  
quantity  
of refrig‐  
erant ex‐  
tracted is  
about  
The required cool‐  
ing output is not  
delivered.  
equal to  
the pre‐  
scribed  
charge  
quantity.  
– Renew  
expan‐  
sion  
valve.  
– Recharge  
refriger‐  
ant cir‐  
cuit.  
– Repeat  
check.  
•
•
High pressure is  
normal,  
•
The  
quantity  
of refrig‐  
erant ex‐  
tracted is  
signifi‐  
Low pressure  
matches the dia‐  
gram value,  
lk  
cantly  
•
The required cool‐  
ing output is not  
delivered.  
less than  
the pre‐  
scribed  
charge  
quantity.  
– Look for  
leaks us‐  
ing leak  
detector  
and recti‐  
fy them.  
– Recharge  
refriger‐  
ant cir‐  
cuit.  
– Repeat  
check.  
10. Checking pressures on vehicles  
137  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
If no fault can be determined and the function of the air condi‐  
tioning system is not OK when the test is repeated, purge refrig‐  
erant circuit with refrigerant R134a (clean) ⇒ page 67 . If thilsk is  
not possible in your workshop, blow through refrigerant circuit with  
compressed air and dry with nitrogen ⇒ page 65 .  
Possible deviation  
from specification  
Possible cause of fault  
Rectifying  
fault  
•
•
High pressure  
rises above speci‐  
fication,  
♦ Restriction or obstruc‐ – Feel the  
tion in the refrigerant  
circuit.  
refriger‐  
ant circuit  
with the  
hand to  
sense the  
tempera‐  
ture gra‐  
dient.  
Low pressure falls ♦ Expansion valve de‐  
quickly to the dia‐  
gram value or low‐  
er,  
fective.  
•
The required cool‐  
ing output is not  
delivered.  
•
At one  
compo‐  
nent a  
tempera‐  
ture gra‐  
dient will  
be detec‐  
ted:  
– If a hose  
or pipe is  
kinked or  
crushed,  
renew it.  
– In case of  
an ob‐  
struction,  
purge re‐  
frigerant  
circuit  
with com‐  
pressed  
air and ni‐  
trogen  
and re‐  
new ex‐  
pansion  
valve.  
•
If no  
faults are  
found:  
– Purge  
(clean)  
refriger‐  
ant circuit  
⇒
page 67 .  
– Repeat  
check.  
138  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
If the air conditioning system is still not operating correctly after  
the refrigerant circuit has been purged with compressed air and  
nitrogen, the expansion valve must be renewed.  
lk  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
High pressure and low pressure ♦ Expansion valve defective.  
– Examine the expan‐  
sion valve for dirt or  
corrosion; renew if  
necessary.  
are normal at first,  
♦ Moisture in the refrigerant circuit.  
•
After a while, the high pressure  
increases beyond the specifica‐  
tion, and the low pressure falls to  
the diagram value or lower,  
– Blow through refrig‐  
erant circuit with  
compressed air and  
nitrogen.  
•
The cooling power called for is  
not delivered.  
– Renew receiver.  
– Repeat the check; if  
the system does not  
operate correctly  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Recharge refriger‐  
ant circuit.  
– Repeat check.  
Note  
When this fault occurs, always renew receiver.  
10. Checking pressures on vehicles  
139  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
•
•
High pressure normal or too high ♦ Too much refrigerant in circuit.  
– Extract some refrig‐  
erant from the re‐  
frigerant circuit.  
(see diagram),  
♦ Expansion valve or air conditioner com‐  
pressor defective.  
The required cooling output is not  
delivered.  
•
The quantity of re‐  
frigerant extracted  
is about equal to the  
prescribed charge  
quantity.  
The air conditioner compressor is  
noisy (especially immediately af‐  
ter being switched on),  
– Renew expansion  
valve.  
– Recharge refriger‐  
ant circuit.  
– Repeat test.  
lk  
•
The quantity of re‐  
frigerant extracted  
is significantly  
greater than the  
prescribed charge  
quantity.  
– Recharge refriger‐  
ant circuit.  
– Repeat check.  
Note  
If the air conditioning system is still not operating correctly when  
the test is repeated, refit the expansion valve and purge the re‐  
frigerant circuit with compressed air and nitrogen. Then renew the  
air conditioner compressor and receiver.  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
High pressure increases only  
slightly above the pressure  
measured when the engine is  
stopped,  
♦ The air conditioner compressor is defec‐ – Purge (clean) refrig‐  
tive.  
erant circuit  
⇒ page 67 .  
– Renew the air condi‐  
tioner compressor  
and receiver.  
•
•
Low pressure falls only slightly,  
The required cooling power is not  
delivered.  
Possible deviation  
from specification  
Possible cause of fault  
Rectifying  
fault  
•
•
High pressure is ♦ Expansion valve or air – Renew  
normal,  
conditioner compres‐  
sor defective.  
expansion  
valve.  
Low pressure is  
too low (see dia‐  
gram),  
– Recharge  
refrigerant  
circuit.  
•
The cooling pow‐  
er required is de‐  
livered.  
– Repeat  
check.  
140  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ If repeated check results in air conditioning system still not  
operating correctly, purge (clean) the refrigerant circuit  
⇒ page 67 . Then renew the air conditioner compressor and  
receiver.  
♦ In this case, the evaporator may ice up although the correct  
quantity of refrigerant is present in the refrigerant circuit.  
Possible deviation from specification  
Possible cause of fault  
Rectifying fault  
•
High-pressure and low-pressure Too much refrigerant oil in circuit.  
are normal,  
– Drain refrigerant cir‐  
cuit.  
•
The required cooling output is not  
delivered.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
•
•
High-pressure and low-pressure  
are normal,  
The air conditioner compressor is  
noisy (especially immediately af‐  
ter being switched on),  
•
The cooling power required is de‐  
livered.  
Note  
♦ Overfilling with refrigerant oil can occur if the refrigerant oil  
level was not checked after the air conditioner compressor  
was renewed.  
♦ If the air conditioner compressor is not to be replaced, drain  
refrigerant oil from air conditioner compressor via the drain  
plug. From the total amount of refrigerant oil, fill 50 g direct into  
air conditioner compressor and fill remainder in refrigerant cir‐  
cuit according to ⇒ vehicle-specific workshop manual .  
lk  
10.4  
Checking systems with an expansion  
valve and reservoir (without regulated  
air conditioner compressor)  
10.4.1  
Test prerequisites  
•
Radiator and condenser must be clean (clean them if neces‐  
sary).  
•
The V-belt for air conditioner compressor and alternator is  
correctly tensioned.  
•
•
•
•
All air ducts, covers and seals are OK and properly installed.  
The flaps reach their end positions.  
The engine is at operating temperature.  
The evaporator and heating do not draw any uncooled air at  
highest fresh air blower speed.  
10. Checking pressures on vehicles  
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Air conditioning system with refrigerant R134a - Edition 10.2014  
With the engine running and the air conditioning system set to full  
power, check the following points:  
•
•
•
•
The fresh air blower is running  
The radiator fan is running or is switched on.  
The fresh air and air recirculation flap is set to “recirculate”.  
o
The ambient temperature is more than 15 C.  
•
The temperature switch for evaporator - E33- is correctly fitted  
and its switching temperatures are correct.  
10.4.2  
Checking  
– Switch off ignition.  
– Connect manifold gauge (air conditioner service station).  
– Read pressure gauge. It may display two results, A and B.  
Ambient temperature in de‐  
grees centigrade  
Pressure likn the refrigerant cir‐  
cuit in bar positive pressure  
+15℃  
+20 ℃  
+30 ℃  
+40 ℃  
3.9  
4.7  
6.7  
9.1  
♦ A- The pressure in the refrigerant circuit is less than shown in  
the table, (insufficient refrigerant in the circuit).  
- Check for leaks using leak detector.  
- The high-pressure safety valve has opened; check the activation  
for the radiator fan referring to the current flow diagram.  
Check refrigerant pipes and refrigerant hoses for bends that have  
too tight radius (restrictions in cross-section) and for external  
damage. If no faults are found, purge the refrigerant circuit.  
♦ B- The pressure in the refrigerant circuit is greater than or  
equal to the value in the table.  
– Start engine.  
– Set air conditioning system to maximum cooling power.  
– Open doors.  
– Open vents in dash panel.  
The air conditioner compressor is driven by the engine, via the V-  
belt and magnetic clutch.  
Note  
♦ If the air conditioner compressor is not being driven, check the  
power supply for the air conditioning system magnetic clutch  
- N25- in accordance with the current flow diagram.  
♦ If power supply is OK, repair magnetic clutch.  
If the air conditioner compressor is not being driven, check the  
refrigerant circuit:  
– Raise engine speed to 2,000 rpm.  
– Observe the manifold gauge.  
142  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
10.4.3  
Specifications  
High-pressure side:  
Increasing from the pressure when the engine is stopped to a  
maximum of 20 bar positive pressure.  
Low-pressure side:  
Decreasing from the pressure when the engine is stopped to 1.3  
bar positive pressure.  
10.5  
Checking systems with a restrictor and  
reservoir and air conditioner compres‐  
sor regulating valve - N280- (with exter‐  
nally regulated air conditioner compres‐  
sor)  
Note  
♦ Connecting air conditioner service station ⇒ page 126 .  
lk  
♦ Observe the test prerequisites ⇒ page 127 .  
– Raise engine speed to 2,000 rpm.  
– Observe air conditioner service station pressure gauge.  
Note  
Switching pressures for the air conditioner compressor regulating  
valve - N280- and the radiator fan - V7- are vehicle-specific.  
⇒ Rep. gr. 87  
10.5.1  
Specifications:  
High-pressure side:  
Rising from starting pressure (when pressure gauge is connec‐  
ted) to 20 bar.  
10. Checking pressures on vehicles  
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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Low-pressure side:  
Falling from starting pressure (when pressure gauge is connec‐  
ted) to diagram value.  
A - Low pressure (measured at the service connection) in bar ab‐  
solute pressure.  
B - Control current for the air conditioner compressor regulating  
valve - N280- .  
C - Permitted tolerance range.  
Note  
♦ Under unfavourable conditions (very high ambient tempera‐  
tures, high atmospheric humidity), the pressure on the high-  
pressure side can increase to a maximum of 29 bar.  
♦ The control current -B- is indicated in the measured values  
block.  
♦ The high pressure is indicated in the measured values block  
⇒ Rep. gr. 87 .  
lk  
♦ The low pressure is adjusted to within tolerances within the  
output range for the air conditioner compressor depending on  
the control current for the air conditioner compressor regulat‐  
ing valve - N280- .  
♦ Under unfavourable conditions (very high ambient tempera‐  
tures, high atmospheric humidity), the output may be insuffi‐  
cient to achieve the specification in every case.  
♦ The set working current for the regulating valve must be great‐  
er than 0.3 A to ensure that the regulating valve is reliably  
activated.  
♦ At the setting for “maximum cooling power”, the control current  
should be approx. 0.8 A (indicated in the measured values  
block) ⇒ Rep. gr. 87 .  
♦ Absolute pressure means that 0 bar corresponds to an abso‐  
lute vacuum. The normal ambient pressure corresponds to 1  
bar absolute pressure. On most pressure gauges, a reading  
of 0 bar corresponds to an absolute pressure of one bar (which  
is confirmed by the existence of - 1 bar marking beneath the  
0 scale marking).  
144  
Rep. gr.00 - Technical data  
lk  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation Possible cause of fault Rectifying fault  
from specification  
•
High pressure  
remains con‐  
♦ Actuation of air con‐ – Check ac‐  
ditioner compressor  
regulating valve -  
N280- is defective.  
tuation of air  
conditioner  
compressor  
regulating  
valve -  
stant or increa‐  
ses only slightly  
(above the pres‐  
sure measured  
when the engine  
is stopped),  
♦ Insufficient refriger‐  
ant in circuit.  
N280- .  
– Look for  
•
•
Low pressure  
falls quickly to  
the diagram val‐  
ue or lower,  
leaks using  
leak detector  
and rectify  
them.  
The required  
– Recharge re‐  
frigerant cir‐  
cuit.  
cooling output is  
not delivered.  
•
•
High pressure is  
normal,  
Low pressure  
matches the dia‐  
gram value,  
•
The required  
cooling output is  
not delivered.  
•
•
High pressure is  
normal,  
Low pressure is  
too low (see dia‐  
gram),  
•
The required  
cooling output is  
not delivered.  
•
•
High pressure is  
normal,  
Low pressure is  
too low (see dia‐  
gram),  
•
The required  
cooling output is  
not delivered.  
Note  
If no fault can be found for this complaint, purge (clean) refrigerant  
circuit with refrigerant R134a ⇒ page 67 . If this is not possible in  
your workshop, blow through refrigerant circuit with compressed  
air and dry with nitrogen ⇒ page 65 .  
10. Checking pressures on vehicles  
145  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation from specifica‐  
tion  
Possible cause of fault  
Rectifying fault  
lk  
•
High pressure increases only  
slightly above the pressure  
measured when the engine is  
stopped,  
♦ Actuation of air conditioner compressor reg‐ – Check actuation of  
ulating valve - N280- is defective.  
air conditioner com‐  
pressor regulating  
valve - N280- .  
♦ The air conditioner compressor is defective.  
•
•
Low pressure falls only slightly,  
– Purge (clean) refrig‐  
erant circuit  
The required cooling output is  
not delivered.  
⇒ page 67 .  
– Renew air condi‐  
tioner compressor.  
•
High pressure rises above spec‐ ♦ Restriction or obstruction in the refrigerant – Feel the refrigerant  
ification,  
circuit.  
circuit with the hand  
to sense the tem‐  
perature gradient.  
•
•
Low pressure falls only slightly,  
The required cooling output is  
not delivered.  
•
At one component a  
temperature gradi‐  
ent will be detected:  
– If a hose or pipe is  
kinked or crushed,  
renew it.  
– In case of an ob‐  
struction, blow  
through refrigerant  
circuit with com‐  
pressed air and ni‐  
trogen.  
•
If no faults are  
found:  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
•
High pressure and low pressure ♦ Moisture in the refrigerant circuit.  
are normal at first, but after a  
– Blow through refrig‐  
erant circuit with  
compressed air and  
nitrogen.  
while, the high pressure increa‐  
ses beyond the specification,  
•
•
The low pressure falls to the di‐  
agram value or lower,  
– Renew reservoir.  
– Repeat the check; if  
the system does not  
operate correctly  
The cooling power called for is  
not delivered.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Recharge refriger‐  
ant circuit.  
– Repeat check.  
146  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation from specifica‐  
tion  
Possible cause of fault  
Rectifying fault  
lk  
•
High pressure is normal,  
♦ Actuation of air conditioner compressor reg‐ – Check actuation of  
ulating valve - N280- is defective.  
air conditioner com‐  
pressor regulating  
valve - N280- .  
•
Low pressure is too low (see di‐  
agram),  
♦ The air conditioner compressor is defective.  
•
The cooling power required is  
delivered.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Renew air condi‐  
tioner compressor.  
Note  
♦ If the fault is “high pressure normal, low pressure too low ” note  
the following: if faulty the evaporator could ice up or the re‐  
quired cooling output is not delivered.  
♦ In this case, the evaporator may ice up although the correct  
quantity of refrigerant is present in the refrigerant circuit.  
♦ Check the measured value of the evaporator output tempera‐  
ture sender - G263- or evaporator temperature sensor -  
G308- .  
♦ Check the actuation of the air conditioner compressor regu‐  
lating valve - N280-  
⇒ Rep. gr. 87  
Possible deviation from specifi‐  
cation  
Possible cause of fault  
Rectifying fault  
•
•
•
High pressure normal or too ♦ Too much refrigerant in circuit.  
high,  
– Extract some refrig‐  
erant from the refrig‐  
erant circuit.  
Low pressure too high (see di‐  
agram),  
•
The quantity of re‐  
frigerant extracted is  
about equal to the  
prescribed charge  
quantity:  
The air conditioner compres‐  
sor is noisy (especially imme‐  
diately after being switched  
on),  
– Renew the air condi‐  
tioner compressor.  
•
The required cooling output is  
not delivered.  
•
The quantity of re‐  
frigerant extracted is  
significantly greater  
than the prescribed  
charge quantity:  
– Recharge refrigerant  
circuit.  
– Repeat check.  
•
•
High-pressure and low-pres‐ ♦ Too much refrigerant oil in circuit.  
sure are normal,  
– Drain refrigerant cir‐  
cuit.  
The required cooling output is  
not delivered.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
10. Checking pressures on vehicles  
147  
lk  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation from specifi‐  
cation  
Possible cause of fault  
Rectifying fault  
•
High-pressure and low-pres‐  
sure are normal,  
•
The air conditioner compres‐  
sor is noisy (especially imme‐  
diately after being switched  
on),  
•
The cooling power required is  
delivered.  
Note  
♦ Overfilling with refrigerant oil can occur if the refrigerant oil  
level was not checked after the air conditioner compressor  
was renewed.  
♦ If the air conditioner compressor is not to be replaced, drain  
refrigerant oil from air conditioner compressor via the drain  
plug. From the total amount of refrigerant oil, fill 50 g direct into  
air conditioner compressor and fill remainder in refrigerant cir‐  
cuit according to ⇒ vehicle-specific workshop manual .  
10.6  
Checking systems with an expansion  
valve, receiver and air conditioner com‐  
pressor regulating valve - N280- (with  
externally regulated air conditioner com‐  
pressor)  
Note  
♦ Connecting air conditioner service station ⇒ page 126 .  
♦ Observe the test prerequisites ⇒ page 127 .  
– Raise engine speed to 2,000 rpm.  
– Observe air conditioner service station pressure gauge.  
Note  
♦ Switching pressures for the air conditioner compressor regu‐  
lating valve - N280- and the radiator fan - V7- are vehicle-  
specific.  
♦ Pressures should be measured at the service connections; the  
location of these connections is vehicle-specific ⇒ Rep. gr.  
87 .  
10.6.1  
Specifications:  
High-pressure side:  
Rising from starting pressure (when pressure gauge is connec‐  
ted) to 20 bar.  
148  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Low-pressure side:  
Falling from starting pressure (when pressure gauge is connec‐  
ted) to diagram value.  
A - Low pressure (measured at the service connection) in bar ab‐  
solute pressure.  
B - Control current for the air conditioner compressor regulating  
valve - N280- .  
C - Permitted tolerance range.  
Note  
♦ Under unfavourable conditions (very high ambient tempera‐  
tures, high atmospheric humidity), the pressure on the high-  
pressure side can increase to a maximum of 29 bar.  
♦ The control current -B- is indicated in the measured values  
lk  
block.  
♦ The high-pressure value measured by the high-pressure  
sender - G65- is indicated in the measured values block ⇒  
Rep. gr. 87 .  
♦ The low pressure is adjusted to within tolerances within the  
output range for the air conditioner compressor depending on  
the control current for the air conditioner compressor regulat‐  
ing valve - N280- .  
♦ Under unfavourable conditions (very high ambient tempera‐  
tures, high atmospheric humidity), the output may be insuffi‐  
cient to achieve the specification in every case.  
♦ The set working current for the regulating valve must be great‐  
er than 0.3 A to ensure that the regulating valve is reliably  
activated.  
♦ At the setting “maximum cooling power”, the control current  
should be approx. 0.65 A to 0.8 A (vehicle-specific, indicated  
in the measured values block) ⇒ Rep. gr. 87 .  
♦ Absolute pressure means that 0 bar corresponds to an abso‐  
lute vacuum. The normal ambient pressure corresponds to 1  
bar absolute pressure. On most pressure gauges, a reading  
of 0 bar corresponds to an absolute pressure of one bar (which  
is confirmed by the existence of - 1 bar marking beneath the  
0 scale marking).  
10. Checking pressures on vehicles  
149  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation Possible cause of fault Rectifying fault  
from specification  
•
High pressure ♦ Actuation of air con‐ – Chelckk ac‐  
remains con‐  
ditioner compressor  
regulating valve -  
N280- is defective.  
tuation of air  
conditioner  
compressor  
regulating  
valve -  
stant or increa‐  
ses only slightly  
(above the pres‐  
sure measured  
when the engine  
is stopped).  
♦ Insufficient refriger‐  
ant in circuit.  
N280- .  
– Look for  
•
•
Low pressure  
falls quickly to  
the diagram val‐  
ue or lower.  
leaks using  
leak detector  
and rectify  
them.  
The required  
– Recharge re‐  
frigerant cir‐  
cuit.  
cooling output is  
not delivered.  
•
•
High pressure is  
normal.  
Low pressure  
matches the di‐  
agram value.  
•
The required  
cooling output is  
not delivered.  
•
•
High pressure is • Insufficient refriger‐ – Extract some  
normal.  
ant in circuit.  
refrigerant  
from the re‐  
frigerant cir‐  
cuit.  
Low pressure  
too low (see dia‐  
gram).  
•
The quantity  
of refrigerant  
extracted is  
significantly  
less than the  
prescribed  
charge  
•
The required  
cooling output is  
not delivered.  
quantity.  
– Look for  
leaks using  
leak detector  
and rectify  
them.  
– Recharge re‐  
frigerant cir‐  
cuit.  
– Repeat  
check.  
•
The quantity  
of refrigerant  
extracted is  
about equal  
to the pre‐  
scribed  
charge  
quantity.  
150  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation Possible cause of fault Rectifying fault  
from specification  
•
Expansion valve de‐ – Renew ex‐  
fective  
pansion  
valve.  
– Recharge re‐  
frigerant cir‐  
cuit.  
– Repeat  
check.  
Note  
♦ If no fault can be found for this complaint, purge (clean) re‐  
frigerant circuit with refrigerant R134a ⇒ page 67 . If this is not  
possible in your workshop, blow through refrigerant circuit with  
compressed air and dry with nitrogen ⇒ page 65 .  
♦ Check the measured values of the evaporator output temper‐  
ature sender - G263- or evaporator temperature sensor -  
G308- and actuation of the air conditioner compressor  
regulating valve - N280- . If the measured value of the evap‐  
orator output temperature sender - G263- or the evaporator  
temperature sender - G308- is faulty, the evaporator may ice  
up or the cooling output will not be achieved.  
♦ If a repeat test after the expansion valve has been renewed  
indicates that the air conditioning system is still not operating  
correctly, refit the expansion valve and purge the refrigerant  
circuit with compressed air and nitrogen. Then renew the air lk  
conditioner compressor and receiver.  
♦ In this case, the evaporator may ice up although the correct  
quantity of refrigerant is present in the refrigerant circuit.  
♦ If the expansion valve is defective (always closed or not open‐  
ing wide enough) the air conditioner compressor regulating  
valve - N280- will be set to maximum power and the low-pres‐  
sure value will fall to the diagram value or less (the air condi‐  
tioner compressor is drawing the refrigerant out of the low-  
pressure side). However, since no refrigerant can flow through  
the expansion valve, the required cooling power is not deliv‐  
ered, and it can be that the high-pressure value does not rise  
at all or not enough, since no energy exchange is occurring.  
Possible deviation from specifica‐  
tion  
Possible cause of fault  
Rectifying fault  
•
High pressure increases only  
slightly above the pressure  
measured when the engine is  
stopped.  
♦ Actuation of air conditioner compressor reg‐ – Check actuation of  
ulating valve - N280- is defective.  
air conditioner com‐  
pressor regulating  
valve - N280- .  
•
•
Low pressure falls only slightly.  
The required cooling output is  
not delivered.  
10. Checking pressures on vehicles  
151  
lk  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation from specifica‐  
tion  
Possible cause of fault  
Rectifying fault  
♦ The air conditioner compressor is defective. – Extract refrigerant.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Renew air condi‐  
tioner compressor.  
– Recharge refriger‐  
ant circuit.  
•
High pressure increases be‐  
yond the specification.  
♦ Actuation of air conditioner compressor reg‐ – Check actuation of  
ulating valve - N280- is defective.  
air conditioner com‐  
pressor regulating  
valve - N280- .  
•
•
Low pressure falls quickly to the  
diagram value or lower.  
The required cooling output is  
not delivered.  
♦ Restriction or obstruction in the refrigerant – Feel the refrigerant  
circuit.  
circuit with the hand  
to sense the tem‐  
perature gradient.  
•
At one component a  
temperature gradi‐  
ent will be detected:  
– If a hose or pipe is  
kinked or crushed,  
renew it.  
– In case of an ob‐  
struction, blow  
through refrigerant  
circuit with com‐  
pressed air and ni‐  
trogen.  
– Recharge refriger‐  
ant circuit.  
– Repeat check.  
•
If no faults are  
found:  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Recharge refriger‐  
ant circuit.  
– Repeat the check; if  
the system does not  
operate correctly  
♦ Expansion valve defective.  
– Extract refrigerant.  
– Renew the expan‐  
sion valve and re‐  
ceiver.  
– Recharge refriger‐  
ant circuit.  
152  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ In this case, the evaporator may ice up although the correct  
quantity of refrigerant is present in the refrigerant circuit.  
lk  
♦ If the expansion valve is defective (always closed or not open‐  
ing wide enough) the air conditioner compressor regulating  
valve - N280- will be set to maximum power and the low-pres‐  
sure value will fall to the diagram value or less (the air condi‐  
tioner compressor is drawing the refrigerant out of the low-  
pressure side). However, since no refrigerant can flow through  
the expansion valve, the required cooling power is not deliv‐  
ered, and it can be that the high-pressure value does not rise  
at all or not enough, since no energy exchange is occurring.  
Possible deviation from specifica‐  
tion  
Possible cause of fault  
Rectifying fault  
•
High pressure and low pressure ♦ Actuation of air conditioner compressor reg‐ – Check actuation of  
are normal at first, but after a  
time the high pressure increa‐  
ses beyond the specification.  
ulating valve - N280- is defective.  
air conditioner com‐  
pressor regulating  
valve - N280- .  
•
After a time, the low pressure  
falls to the diagram value or low‐  
er.  
•
•
The cooling power called for is  
not delivered.  
High pressure and low pressure ♦ Moisture in the refrigerant circuit.  
are normal at first, but after a  
– Extract refrigerant.  
longer drive, the low pressure  
– Blow through refrig‐  
erant circuit with  
compressed air and  
nitrogen.  
falls to below the specification  
(evaporator iced up).  
– Renew receiver to‐  
gether with dryer.  
– Evacuate refriger‐  
ant circuit for at  
least 3 hours.  
– Recharge refriger‐  
ant circuit.  
– Repeat the check; if  
the function is not  
OK  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Recharge refriger‐  
ant circuit.  
– Repeat check.  
10. Checking pressures on vehicles  
153  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ If this complaint occurs after a longer period of operation or  
only occasionally (the low pressure falls below the specifica‐  
tion and the evaporator ices up) it is sufficient only to renew  
the dryer (fitted within the receiver). Check the quantity of re‐  
frigerant oil. Then evacuate the refrigerant circuit for at least 3  
hours.  
♦ In case of this complaint, it is not initially necessary to purge  
the refrigerant circuit with compressed air and nitrogen, since  
as a rule only a small quantity of moisture will have accumu‐  
lated in the system, which can be removed by a longer evac‐  
uation period.  
lk  
♦ In this case, the evaporator may ice up although the correct  
quantity of refrigerant is present in the refrigerant circuit.  
Possible deviation from specifica‐  
tion  
Possible cause of fault  
Rectifying fault  
•
High pressure normal, low pres‐ ♦ Actuation of air conditioner compressor reg‐ – Check actuation of  
sure too low (see diagram), the  
required cooling power is deliv‐  
ered.  
ulating valve - N280- is defective.  
air conditioner com‐  
pressor regulating  
valve - N280- .  
♦ Expansion valve defective.  
– Extract refrigerant.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Renew the expan‐  
sion valve and re‐  
ceiver.  
– Recharge refriger‐  
ant circuit.  
– Repeat the check; if  
the system does not  
operate correctly  
– Renew the air con‐  
ditioner compres‐  
sor.  
♦ The air conditioner compressor is defective. – Extract refrigerant.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Renew the air con‐  
ditioner compres‐  
sor.  
– Recharge refriger‐  
ant circuit.  
– Repeat check.  
154  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ If the fault is “high pressure normal, low pressure too low ” note  
the following: if faulty the evaporator could ice up or the re‐  
quired cooling output is not delivered.  
♦ In this case, the evaporator may ice up although the correct  
quantity of refrigerant is present in the refrigerant circuit.  
lk  
♦ Check the measured values of the evaporator output temper‐  
ature sender - G263- or evaporator temperature sensor -  
G308- and actuation of the air conditioner compressor  
regulating valve - N280- . If the measured value at the high-  
pressure sender - G65- is faulty, the evaporator can ice up or  
the required cooling power is not delivered.  
♦ If the defect is in the air conditioner compressor regulating  
valve - N280- (the regulating valve is not activated, but the air  
conditioner compressor still runs), it is not necessary to blow  
through the refrigerant circuit. If this fault occurs, it is sufficient  
to renew the air conditioner compressor (check the refrigerant  
oil quantity in the air conditioner compressor).  
♦ If the expansion valve is defective (always closed or not open‐  
ing wide enough) the air conditioner compressor regulating  
valve - N280- will be set to maximum power and the low-pres‐  
sure value will fall to the diagram value or less (the air condi‐  
tioner compressor is drawing the refrigerant out of the low-  
pressure side). However, since no refrigerant can flow through  
the expansion valve, the required cooling power is not deliv‐  
ered, and it can be that the high-pressure value does not rise  
at all or not enough, since no energy exchange is occurring.  
⇒ Rep. gr. 87  
Possible deviation from specifi‐  
cation  
Possible cause of fault  
Rectifying fault  
•
•
•
High pressure normal or too ♦ Actuation of air conditioner compressor reg‐ – Check actuation of  
high.  
ulating valve - N280- is defective.  
air conditioner com‐  
pressor regulating  
valve - N280- .  
Low pressure too low (see di‐ ♦ Too much refrigerant in circuit.  
agram).  
– Extract some refrig‐  
erant from the refrig‐  
erant circuit.  
The air conditioner compres‐  
sor is noisy (especially imme‐  
diately after being switched  
on).  
•
The quantity of re‐  
frigerant extracted is  
about equal to the  
prescribed charge  
quantity:  
•
The required cooling output is  
not delivered.  
– Renew the air condi‐  
tioner compressor.  
•
The quantity of re‐  
frigerant extracted is  
significantly greater  
than the prescribed  
charge quantity:  
– Recharge refrigerant  
circuit.  
– Repeat check.  
10. Checking pressures on vehicles  
155  
lk  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Possible deviation from specifi‐  
cation  
Possible cause of fault  
Rectifying fault  
♦ Too much refrigerant oil in circuit.  
– Drain refrigerant cir‐  
cuit.  
•
The quantity of re‐  
frigerant extracted is  
about equal to the  
prescribed charge  
quantity.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Recharge refrigerant  
circuit.  
– Repeat check.  
♦ Expansion valve defective.  
– Drain refrigerant cir‐  
cuit.  
– Renew the expan‐  
sion valve and re‐  
ceiver.  
– Recharge refrigerant  
circuit.  
– Repeat the check; if  
the system does not  
operate correctly  
– Renew the air condi‐  
tioner compressor.  
♦ The air conditioner compressor is defective. – Drain refrigerant cir‐  
cuit.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Renew the air condi‐  
tioner compressor.  
•
The quantity of re‐  
frigerant extracted is  
significantly greater  
than the prescribed  
charge quantity.  
– Recharge refrigerant  
circuit.  
– Repeat check.  
156  
Rep. gr.00 - Technical data  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ If the defect is in the air conditioner compressor regulating  
valve - N280- (the regulating valve is not activated, but the air  
conditioner compressor still runs), it is not necessary to blow  
through the refrigerant circuit. If this fault occurs, it is sufficient  
to renew the air conditioner compressor (check the refrigerant  
oil quantity in the air conditioner compressor).  
♦ Overfilling with refrigerant oil can occur if the refrigerant oil  
level was not checked after the air conditioner compressor  
was renewed.  
♦ If the air conditioner compressor is not to be replaced, drain  
refrigerant oil from air conditioner compressor via the drain  
plug. From the total amount of refrigerant oil, fill 50 g direct into  
air conditioner compressor and fill remainder in refrigerant cir‐  
cuit according to ⇒ vehicle-specific workshop manual .  
♦ If the expansion valve is defective (always closed or not open‐  
ing wide enough) the air conditioner compressor regulating  
valve - N280- will be set to maximum power and the low-pres‐  
sure value will fall to the diagram value or less (the air condi‐  
tioner compressor is drawing the refrigerant out of the low-  
pressure side). However, since no refrigerant can flow through  
the expansion valve, the required cooling power is not deliv‐  
ered, and it can be that the high-pressure value does not rise  
at all or not enough, since no energy exchange is occurring.  
Possible deviation from specifi‐  
cation  
Possible cause of fault  
Rectifying fault  
•
High pressure and low pres‐ ♦ Actuation of air conditioner compressor reg‐ – Check actuation of  
sure are normal.  
ulating valve - N280- is defective.  
air conditioner com‐  
pressor regulating  
valve - N280- .  
lk  
•
The required cooling output is ♦ Too much refrigerant oil in circuit.  
not delivered.  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
•
•
High pressure and low pres‐ ♦ Too much refrigerant oil in circuit.  
sure are normal.  
– Drain refrigerant cir‐  
cuit.  
The air conditioner compres‐  
sor is noisy (especially imme‐  
diately after being switched  
on).  
– Purge (clean) refrig‐  
erant circuit  
⇒ page 67 .  
– Recharge refrigerant  
circuit.  
•
The cooling power required is  
delivered.  
– Repeat check.  
♦ Expansion valve defective.  
– Renew expansion  
valve.  
10. Checking pressures on vehicles  
157  
Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...  
Air conditioning system with refrigerant R134a - Edition 10.2014  
Note  
♦ Overfilling with refrigerant oil can occur if the refrigerant oil  
level was not checked after the air conditioner compressor  
was renewed.  
♦ If the air conditioner compressor is not to be replaced, drain  
refrigerant oil from air conditioner compressor via the drain  
plug. From the total amount of refrigerant oil, fill 50 g direct into  
air conditioner compressor and fill remainder in refrigerant cir‐  
cuit according to ⇒ vehicle-specific workshop manual .  
♦ If the expansion valve is defective (always open) the evapo‐  
rator temperature will no longer be regulated so that only  
gaseous refrigerant exits the evaporator. It is then possible  
that under certain operating conditions, drops of liquid will be  
drawn into the air conditioner compressor, which will hen  
cause noise (because liquid is incompressible).  
10.7  
With expansion valve, receiver and  
lk  
electrical air conditioner compressor  
Note  
The electrical air conditioner compressor does not have an air  
conditioner compressor regulating valve - N280- . Regulation  
takes place via the speed of the air conditioner compressor. The  
air conditioner compressor contains the control electronics and a  
G-supercharger that impels the refrigerant.  
158  
Rep. gr.00 - Technical data  

Related Topics

10.1 Checking pressures in refrigerant circuit... 10.2 Checking systems with a restrictor and collector... 10.3 Checking systems with an expansion valve and reservoir... 10.4 Checking systems with expansion valve and reservoir... 10.5 Checking systems with a restrictor and reservoir... 10.6 Checking systems with an expansion valve, receiver... 10.7 With expansion valve, receiver and electrical compressor

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