Get Air conditioning system -> 2.14.5 Checking pressures with air conditioning system switched on - vehicles with electrical air conditioning compressor Guide for Volkswagen Touran 4 Door Second Generation (2015-2022)

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ In the event of the following fault “High pressure normal, low

pressure too low”, please note the following: With this fault,

there is a chance that the evaporator could ice up even though

the refrigerant volume in the circuit is OK.

♦ If the fault exists in a shut-off valve that may be installed in the

system (shut-off valve does not open), the refrigerant circuit

needs to be cleaned (flushed with R1234yf refrigerant

⇒ “1.6 Cleaning refrigerant circuit”, page 92 ). With this fault,

it is sufficient to check actuation of the shut-off valve. If this is

OK, renew the shut-off valve.

♦ If the fault is in the air conditioner compressor regulating valve

- N280- (the regulating valve is not activated, but the air con‐

ditioner compressor still runs), it is not necessary to clean the

refrigerant circuit (flush with R1234yf refrigerant

⇒ “1.6 Cleaning refrigerant circuit”, page 92 ). In this case it is

sufficient to renew the air conditioner compressor (observe

quantity of refrigerant oil in 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 extracts refrigerant from the low pressure

side). However, since no refrigerant can flow through the ex‐

pansion valve, the required cooling output is not reached, the

high pressure may also not rise or only marginally since no

energy exchange is taking place. With this fault, it is not nec‐

essary to clean the refrigerant circuit (flush with R1234yf re‐

frigerant ⇒ “1.6 Cleaning refrigerant circuit”, page 92 ).

Renewing the expansion valve is sufficient.

♦ Check the measured values of the evaporator output temper‐

ature sender - G263- and actuation of the air conditioner

compressor regulating valve - N280- . If the measured value

lk

of -G263- is faulty, the evaporator could ice up or the cooling

output may not be reached ⇒ Vehicle diagnostic tester in “Gui‐

ded Fault Finding” mode - air conditioning system.

Possible deviation from specification during pressure test

♦ The air conditioner compressor is noisy (especially immediately after being switched on),

♦ The requisite cooling output is reached.

♦ High pressure normal or too high

♦ The low pressure is normal or too high (the specification is not always reached)

Possible causes for deviation from specification and rectification

2. Working with air conditioner service station

GETth

201

lk

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Possible deviation from specification during pressure test

♦ Actuation of the air conditioner compressor regulating valve - N280- is defective.

– Check actuation of the air conditioner compressor regulating valve - N280- and repair if necessary ⇒ Vehicle

diagnostic tester in “Guided Fault Finding” mode - air conditioning system.

♦ Check function of -N280- ; if necessary remove -N280- and check for dirt ⇒ Vehicle diagnostic tester in

“Guided Fault Finding” mode - air conditioning system, ⇒ “1.5 Renewing components”, page 79 and ⇒

Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (workshop manual for specific vehicle).

♦ Renew -N280- or air conditioner compressor ⇒ “1.5 Renewing components”, page 79 and ⇒ Heating, air

conditioning; Rep. gr. 87 ; Air conditioner compressor (vehicle-specific workshop manual).

♦ If dirt is found in the refrigerant circuit, clean the refrigerant circuit (flush with R1234yf refrigerant) and renew

the expansion valve and desiccant bag/desiccant cartridge (or renew the receiver/reservoir)

⇒ “1.6 Cleaning refrigerant circuit”, page 92 , ⇒ “1.5 Renewing components”, page 79 and ⇒ Heating, air

conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific workshop manual).

♦ Too much refrigerant or refrigerant oil in the refrigerant circuit

– Extract refrigerant from the refrigerant circuit ⇒ “2.4 Emptying refrigerant circuit”, page 137 .

– If the extracted refrigerant volume is considerably greater (more than 100 g) than the prescribed fill volume

⇒ Heating, air conditioning; Rep. gr. 00 ; Technical data (vehicle-specific workshop manual), there was

too much refrigerant in the refrigerant circuit Recharge refrigerant circuit and repeat test.

– If the extracted refrigerant volume equates to the prescribed fill volume or is marginally higher than the

prescribed fill volume (less than 100 g) ⇒ Heating, air conditioning; Rep. gr. 00 ; Technical data (vehicle-

specific workshop manual), there is too much refrigerant oil in the refrigerant circuit Clean the refrigerant

circuit (flush with R1234yf refrigerant) ⇒ “1.6 Cleaning refrigerant circuit”, page 92 , recharge with the correct

volume of refrigerant and refrigerant oil and repeat the test.

♦ Expansion valve defective

♦ If a shut-off valve is installed in the refrigerant circuit and it does not open correctly or at all ⇒ Heating, air

conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific workshop manual).

– If fitted, check the function of the installed shut-off valve ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrig‐

erant circuit (vehicle-specific workshop manual).

– Renew the expansion valve and desiccant bag/desiccant cartridge (or reservoir/receiver)

⇒ “1.5 Renewing components”, page 79 and ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

♦ The air conditioner compressor is defective.

– If it is not possible to find a fault on any of the components and the extracted refrigerant volume equates

to the specifications, clean the refrigerant circuit (flush with R1234yf refrigerant)

⇒ “1.6 Cleaning refrigerant circuit”, page 92 . If when cleaning the refrigerant circuit no overly high volume

of refrigerant is found, renew the air conditioner compressor ⇒ “1.5 Renewing components”, page 79 , ⇒

Heating, air conditioning; Rep. gr. 00 ; Repair instructions; Checking cooling output (vehicle-specific work‐

shop manual) and ⇒ Heating, air conditioning; Rep. gr. 87 ; Air conditioner compressor (vehicle-specific

workshop manual).

Final measures

– Recharge the refrigerant circuit ⇒ “2.6 Charging refrigerant circuit”, page 146

– Repeat the test

⇒ “2.14.4 Checking pressures with air conditioning system switched on - vehicles with mechanical air

conditioning compressor”, page 183

202

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ The cause for this fault could also be too much refrigerant oil

in the refrigerant circuit. Overfilling with refrigerant oil can oc‐

cur if the refrigerant oil level was not checked after the air

conditioner compressor was renewed. If there is too much re‐

frigerant oil in the refrigerant circuit, clean the refrigerant circuit

(flush with R1234yf refrigerant).

⇒ “1.6 Cleaning refrigerant circuit”, page 92

♦ If the expansion valve (or a shut-off valve that may be installed

lk

in the system) is defective (always closed or not opening wide

enough) the air conditioner compressor regulating valve -

N280- will be set to maximum power and the low pressure

value will fall to the diagram value or less (the air conditioner

compressor extracts refrigerant from the low pressure side).

Since no refrigerant can flow through the expansion valve,

however, the cooling output is not reached and the high pres‐

sure may also not increase or only increase slightly owing to

there being no energy exchange ⇒ Vehicle diagnostic tester

in “Guided Fault Finding” mode - air conditioning system and

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

Possible deviation from specification during pressure test

♦ The required cooling output is not reached.

♦ The high pressure and low pressure equate to the specification

Possible causes for deviation from specification and rectification

2. Working with air conditioner service station

GETth

203

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Possible deviation from specification during pressure test

♦ There is too little refrigerant in the refrigerant circuit.

– Extract refrigerant from the refrigerant circuit ⇒ “2.4 Emptying refrigerant circuit”, page 137 .

– If the extracted refrigerant volume is considerably less than the specified fill volume (more than 100 g less)

⇒ Heating, air conditioning; Rep. gr. 00 ; Technical data (vehicle-specific workshop manual), search for

the leak and rectify the cause ⇒ “1.4 Investigating leaks”, page 68

– The extracted refrigerant volume roughly equates to the prescribed fill volume, measured value of evapo‐

rator output temperature sender - G263- , actuation of air conditioner compressor regulating valve - N280- ,

function of expansion valve faulty or fault in a different component (see below).

♦ Measured value of evaporator output temperature sender - G263- faulty.

– Check measured value and installation of -G263- ⇒ Vehicle diagnostic tester in “Guided Fault Finding”

function - air conditioning system and ⇒ Heating, air conditioning; Rep. gr. 87 ; Overview of fitting locations

- air conditioning system ⇒ Heating, air conditioning; Rep. gr. 87 ; Air conditioner compressor (vehicle-

specific workshop manual).

♦ Actuation of the air conditioner compressor regulating valve - N280- is defective.

– Check the actuation of -N280- and, if necessary, repair ⇒ Vehicle diagnostic tester in “Guided Fault Finding”

mode - air conditioning system.

♦ Expansion valve defective

lk

♦ If a shut-off valve is installed in the refrigerant circuit and it does not open correctly or at all ⇒ Heating, air

conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific workshop manual).

– Touch the refrigerant circuit by hand to feel for a drop in temperature ⇒ Heating, air conditioning; Rep. gr.

87 ; Refrigerant circuit (vehicle-specific workshop manual). If a drop in temperature is felt on a component,

if there is a kink or bottle-neck in the hose or pipeline, renew this component. In the event of a blockage or

if no fault can be found, clean the refrigerant circuit (flush with R1234yf refrigerant)

⇒ “1.6 Cleaning refrigerant circuit”, page 92

– If fitted, check the function of the installed shut-off valve ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrig‐

erant circuit (vehicle-specific workshop manual).

– Renew the expansion valve and desiccant bag/desiccant cartridge (or reservoir/receiver)

⇒ “1.5 Renewing components”, page 79 and ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

♦ Too much refrigerant oil in the refrigerant circuit

– If the extracted refrigerant volume equates to the prescribed fill volume or is marginally higher than the

prescribed fill volume (less than 100 g) ⇒ Heating, air conditioning; Rep. gr. 00 ; Technical data (vehicle-

specific workshop manual), there is too much refrigerant oil in the refrigerant circuit Clean the refrigerant

circuit (flush with R1234yf refrigerant) ⇒ “1.6 Cleaning refrigerant circuit”, page 92 , recharge with the correct

volume of refrigerant and refrigerant oil and repeat the test.

♦ Expansion valve defective

♦ If a shut-off valve is installed in the refrigerant circuit and it does not open correctly or at all ⇒ Heating, air

conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific workshop manual).

– If fitted, check the function of the installed shut-off valve ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrig‐

erant circuit (vehicle-specific workshop manual).

– Renew the expansion valve and desiccant bag/desiccant cartridge (or reservoir/receiver)

⇒ “1.5 Renewing components”, page 79 and ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

Final measures

– Recharge the refrigerant circuit ⇒ “2.6 Charging refrigerant circuit”, page 146

– Repeat the test

⇒ “2.14.4 Checking pressures with air conditioning system switched on - vehicles with mechanical air

conditioning compressor”, page 183

204

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ Check the measured values of the evaporator output temper‐

lk

ature sender - G263- and actuation of -N280- . If the measured

value of -G263- is faulty, the evaporator could ice up or the

cooling output will not be reached ⇒ Vehicle diagnostic tester

in “Guided Fault Finding” mode - air conditioning system and

⇒ Heating, air conditioning; Rep. gr. 87 ; Overview of fitting

locations - air conditioning system (vehicle-specific workshop

manual).

♦ Overfilling with refrigerant oil can occur if the refrigerant oil

level was not checked after the air conditioner compressor

was renewed.

♦ If the expansion valve is defective (always open) the evapo‐

rator temperature will no longer be controlled 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).

♦ If there is too much refrigerant oil in the circuit, empty the air

conditioner compressor and, if fitted, renew the reservoir/re‐

ceiver (or desiccant cartridge) ⇒ Heating, air conditioning;

Rep. gr. 87 ; Refrigerant circuit (vehicle-specific workshop

manual). After cleaning the refrigerant circuit (flushing with

R1234yf refrigerant)

⇒ “1.6 Cleaning refrigerant circuit”, page 92 , pour the correct

amount of refrigerant oil in the circuit ⇒ Heating, air condi‐

tioning; Rep. gr. 00 ; Technical data (vehicle-specific work‐

shop manual).

2.14.5

Checking pressures with air condition‐

ing system switched on - vehicles with

electrical air conditioning compressor

Checking pressures ⇒ page 205

Specifications for pressures in refrigerant circuit on vehicles with‐

out heat pump ⇒ page 210

Specifications for pressures in refrigerant circuit on vehicles with

heat pump ⇒ page 234

Checking pressures

Note

Work on the refrigerant circuit that involves the air conditioner

service station (checking the pressures in this case) can usually

be carried out without the need to de-energise the high-voltage

system.

– To minimise the number of automatic engine starts during

testing and measuring while operational readiness is active,

charge the vehicle batteries e.g. with battery charger 60A -

VAS 5904- in battery back-up mode ⇒ Electrical system; Rep.

gr. 27 ; Battery; Charging battery and ⇒ Electrical system;

Rep. gr. 93 ; General warnings for work on the high-voltage

system .

– For test and measurement work that requires the vehicle's

drive system to be active (READY) or the ignition to be switch‐

ed on, move the selector lever to position “P”, activate the

2. Working with air conditioner service station

GETth

205

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

parking brake and arrange the tools needed so that they can‐

not come into contact with moving components of the engine

and so that they cannot even come near to components that

turn when the engine is running.

Note

♦ Also move the selector lever to position “P”, and activate the

parking brake before performing test and measurement work

for which the ignition must be switched on but where the ve‐

hicle's drive system does not need to be active (READY).

lk

♦ Operational readiness (vehicle’s drive system) is displayed in

the control unit in dash panel insert - J285- via the “Powerme‐

ter” ⇒ owner's manual .

♦ Activating and deactivating vehicle drive system ⇒ Owner's

manual (observe display in control unit in dash panel insert -

J285- while doing so).

– On vehicles with high-voltage system, switch off “stationary air

conditioning” function (deactivate)⇒ Owner's Manual and ⇒

Operating instructions of infotainment / MMI .

– Switch off ignition.

– Connect the air conditioner service station

⇒ “2.2 Connecting air conditioner service station to refrigerant

circuit”, page 131 .

Note

If a problem is encountered in just one evaporator on vehicles with

two evaporators (one evaporator in the heater and air conditioning

unit and one evaporator on the heat exchanger for high-voltage

battery), check the pressures in the refrigerant circuit Check the

line connection between the evaporator that is causing the prob‐

lem and the end of the line at the distribution point for the refrig‐

erant lines (for a bottle-neck or blockage). If no fault can be found,

empty the refrigerant circuit and recharge it with the prescribed

amount of refrigerant. Then check the pressures and the cooling

output of the air conditioning system again. If the problem per‐

sists, check / renew the following components: If the problem is

only encountered at the evaporator in the heating and air condi‐

tioning unit, check the evaporator in the heating and air condi‐

tioning unit (it is open in unactuated state and allows refrigerant

to flow through). Renew the expansion valve on the evaporator in

the heater and air conditioning unit if no fault can be found in the

shut-off valve. If the problem is only encountered on the evapo‐

rator in the heat exchanger for high-voltage battery, check actua‐

tion of the shut-off valve on the expansion valve on the evaporator

in the heat exchanger for high-voltage battery (it is closed in un‐

actuated state and does not allow refrigerant to flow through) ⇒

Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-

specific workshop manual).

Conditions for testing

•

The air conditioner service station is connected to the refrig‐

erant circuit

⇒ “2.2 Connecting air conditioner service station to refrigerant

circuit”, page 131 .

•

Observe the conditions for testing pressures in the refrigerant

circuit with the ignition switched off ⇒ page 176 .

The pressures in the refrigerant circuit comply with the speci‐

fications with the ignition switched off

206

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

⇒ “2.14.3 Checking pressures in the refrigerant circuit with the

ignition switched off”, page 176 .

•

Observe the conditions for testing the^lc^kooling output ⇒ Heat‐

ing, air conditioning; Rep. gr. 00 ; Repair instructions; Check‐

ing cooling output (vehicle-specific workshop manual).

Note

♦ The switching pressures for actuation of the electrical air con‐

ditioner compressor - V470- and the radiator fan - V7- are

vehicle-specific ⇒ Vehicle diagnostic tester in “Guided Fault

Finding” mode - air conditioning system and battery regulation.

♦ The pressures must be measured at the service connections;

the fitting locations of these connections are vehicle-specific

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

•

The engine is at operating temperature (at an ambient tem‐

perature less than 25°C).

Note

♦ Should the engine not be at operating temperature, take the

vehicle for a short drive.

♦ To test the cooling output, the engine does not have to be at

operating temperature. However, to demand a certain cooling

output from the air conditioning system at an ambient temper‐

ature of less than 25°C, the engine is required to be warm if

ambient temperatures are low.

•

To minimise the number of automatic engine starts during

testing and measuring while operational readiness is active,

charge the vehicle batteries e.g. with battery charger 60A -

VAS 5904- in battery back-up mode ⇒ Electrical system; Rep.

gr. 27 ; Battery; Charging battery and ⇒ Electrical system;

Rep. gr. 93 ; General warnings for work on the high-voltage

system .

– Activate operational readiness (engine must not run) ⇒ own‐

er's manual .

– Set the air conditioning system to maximum cooling output ⇒

Heating, air conditioning; Rep. gr. 00 ; Repair instructions;

Checking cooling output (vehicle-specific workshop manual).

•

The electrical air conditioner compressor - V470- is actuated

and runs ⇒ Vehicle diagnostic tester in “Guided Fault Finding”

mode - air conditioning system and battery regulation as well

as ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

2. Working with air conditioner service station

GETth

207

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

lk

Note

♦ Actuation of the electrical air conditioning compressor is initi‐

ated by the vehicle electronics. The engine speed has no

influence on the cooling output of the air conditioning system.

♦ The air conditioner compressor is currently not activated at the

maximum specified speed (of approx. 8500 rpm) when the

vehicle is stationary or driving slowly (up to a vehicle speed of

45 km/h). The air conditioner compressor speed is restricted

to approx. 5000 rpm.

♦ Actuation of the electrical air conditioning compressor can be

monitored by guided fault finding ⇒ Vehicle diagnostic tester

in “Guided Fault Finding” mode - air conditioning system and

battery regulation.

♦ All of the conditions for testing marked with * are pertinent to

a certain vehicle and are described in the vehicle-specific

workshop manual ⇒ Heating, air conditioning; Rep. gr. 00 ;

Repair instructions; Checking cooling output (vehicle-specific

workshop manual).

If the air conditioner compressor is not actuated with operational

readiness active:

– Determine the cause, e.g. by interrogating the event memory

of the air conditioning system, and rectify it ⇒ Vehicle diag‐

nostic tester in “Guided Fault Finding” mode - air conditioning

system and battery regulation.

•

The radiator and condenser are clean (clean if necessary) * ⇒

Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (ve‐

hicle-specific workshop manual) and ⇒ Engine, mechanicals;

Rep. gr. 19 ; Radiator/radiator fan .

•

The heat insulation on the expansion valve is OK and mounted

correctly * ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrig‐

erant circuit (vehicle-specific workshop manual).

The air ducts, covers and seals are OK and mounted correctly

* ⇒ Heating, air conditioning; Rep. gr. 87 ; Overview of fitting

locations - air conditioning system (vehicle-specific workshop

manual).

•

No faults are found during diagnosis of the air conditioning

system (with operational readiness (vehicle’s drive system)

active and the air conditioning system switched on). No com‐

pressor deactivation condition is shown in the measured valve

block ⇒ Vehicle diagnostic tester in “Guided Fault Finding”

mode - air conditioning system and battery regulation.

The various pressure/temperature senders and temperature

sensors on or in the refrigerant circuit supply plausible values

during operation of the air conditioning system, check ⇒ Ve‐

hicle diagnostic tester in “Guided Fault Finding” mode and ⇒

Heating, air conditioning; Rep. gr. 87 ; Overview of fitting lo‐

cations - air conditioning system . If no fault can be found,

extract the refrigerant.

•

The rate of air flow through the dust and pollen filter is not

impaired by dirt * ⇒ Heating, air conditioning; Rep. gr. 87 ;

Overview of fitting locations - air conditioning system (vehicle-

specific workshop manual).

The heater and air conditioner does not draw any secondary

air at highest fresh air blower speed. evaporator and heater

not drawing in secondary air at maximum fresh-air blower

speed * ⇒ Heating, air conditioning; Rep. gr. 00 ; Repair in‐

structions; Checking cooling output (vehicle-specific work‐

shop manual).

208

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

•

The air duct flaps in the heater and air conditioner unit, heater

and evaporator reach their end position * ⇒ Heating, air con‐

ditioning; Rep. gr. 00 ; Repair instructions; Checking cooling

output (vehicle-specific workshop manual).

Fresh-air intake ducts beneath bonnet and in passenger com‐

partment as well as corresponding water drain valves OK* ⇒

Heating, air conditioning; Rep. gr. 87 ; Overview of fitting lo‐

cations - air conditioning system (vehicle-specific workshop

manual).

•

The vehicle is not exposed to the sun's rays ⇒ Heating, air

conditioning; Rep. gr. 00 ; Repair instructions; Checking cool‐

ing output (vehicle-specific workshop manual).

•

Ambient temperature is above 15°C.

All dash panel air vents are open.*

Setting e.g. on operating and display unit for front air conditioning

system - E87- (and operating and display unit for rear air condi‐

tioning system - E265- on vehicles with two heater and air con‐

ditioning units) * ⇒ Heating, air conditioning system; Rep. gr. 00 ;

Repair instructions; Checking cooling output (vehicle-specific

workshop manual) and ⇒ Heating, air conditioning; Rep. gr. 87 ;

Overview of fitting locations - air conditioning system .

Setting e.g. on -E87- *:

– Select “Auto” mode (air conditioner compressor switched on).

– Set temperature to “cold” or “LO” for the driver and front pas‐

senger side (and the rear on the left and right in vehicles with

two heating and air conditioning units).*

Setting on -J301- *:

– Press A/C button and Rec or recirculate buttons.*

lk

– Turn rotary temperature knob in direction of “cold” stop.*

– Set rotary fresh air blower switch to “4” (maximum fresh air

blower speed).*

The following conditions for testing should then be met in the sys‐

tem:

•

The radiator fan - V7- is running or the radiator fan - V7- and

radiator fan 2 - V177- are running (at least stage 1) * ⇒ Heat‐

ing, air conditioning; Rep. gr. 00 ; Repair instructions; Check‐

ing cooling output (vehicle-specific workshop manual) and ⇒

Engine, mechanicals; Rep. gr. 19 ; Radiator/radiator fan .

Note

On certain versions, the radiator fan cuts in only after the pressure

in the refrigerant circuit has exceeded a pre-set value ⇒ Vehicle

diagnostic tester in “Guided Fault Finding” mode - air conditioning

system and battery regulation.

•

The fresh air blower - V2- (and the rear fresh air blower - V80-

on vehicles with two heating and air conditioning units) is

running at maximum speed.*

The air recirculation flap/fresh air flap is in “recirculation

mode” (within 1 minute after starting the vehicle, the air flow

flap closes and the air recirculation flap opens).*

The coolant shut-off valve is closed * ⇒ Heating, air condi‐

tioning; Rep. gr. 00 ; Repair instructions; Checking cooling

output (vehicle-specific workshop manual) and ⇒ Heating, air

2. Working with air conditioner service station

GETth

209

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

conditioning; Rep. gr. 87 ; Overview of fitting locations - air

conditioning system (vehicle-specific workshop manual).

•

The valves of the pump-valve unit are closed and the coolant

circulation pump is not delivering * ⇒ Heating, air conditioning;

Rep. gr. 00 ; Repair instructions; Checking cooling output

(vehicle-specific workshop manual) and ⇒ Heating, air con‐

ditioning; Rep. gr. 87 ; Overview of fitting locations - air

conditioning system (vehicle-specific workshop manual).

Note

♦ Actuation of the electrical air conditioning compressor is initi‐

ated by the vehicle electronics. The engine speed has no

influence on the cooling output of the air conditioning system

⇒ Vehicle diagnostic tester in “Guided Fault Finding” mode -

air conditioning system and battery regulation.

♦ The air conditioner compressor is currently not activated at the

maximum specified speed (of approx. 8500 rpm) when the

vehicle is stationary or driving slowly (up to a vehicle speed of

45 km/h). The air conditioner compressor speed is restricted

to approx. 5000 rpm.

♦ Actuation of the electrical air conditioning compressor can be

monitored by guided fault finding ⇒ Vehicle diagnostic tester

in “Guided Fault Finding” mode - air conditioning system and

battery regulation.

♦ The pressures must be measured at the service connections;

the fitting locations of these connections are vehicle-specific

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

Specifications for pressures in the refrigerant circuit

♦ Specifications for pressures in refrigerant circuit on vehicles

without heat pump ⇒ page 210

lk

♦ Specifications for pressures in refrigerant circuit on vehicles

with heat pump ⇒ page 234

Note

♦ The specified and actual speeds for actuation of the electrical

air conditioner compressor - V470- and the radiator fan - V7-

are vehicle-specific ⇒ Vehicle diagnostic tester in “Guided

Fault Finding” mode - air conditioning system and battery reg‐

ulation.

♦ The pressures must be measured at the service connections;

the fitting locations of these connections are vehicle-specific

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

Specifications for pressures in refrigerant circuit on vehicles with‐

out heat pump

♦ Observe the test prerequisites ⇒ page 205 .

– Watch the pressure display (e.g. pressure gauge) of the air

conditioner service station .

210

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ The switching pressures for actuation of the electrical air con‐

ditioner compressor - V470- and the radiator fan -V7- / -V177-

are vehicle-specific ⇒ Vehicle diagnostic tester in “Guided

Fault Finding” mode - air conditioning system and battery reg‐

ulation.

♦ The pressures must be measured at the service connections;

the fitting locations of these connections are vehicle-specific

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

High-pressure side:

From the output pressure (when the pressure gauge is connec‐

ted) rising up to a maximum overpressure of 20 bar (depending

on the ambient temperature and operating conditions of the air

conditioning system).

Low-pressure side:

From the output pressure (when connecting the pressure gauge)

dropping to a value of between 1.5 and 2.3 bar absolute pressure

(depending on required cooling output).

Speed of air conditioner compressor:

lk

Between 800 and 8500 rpm depending on the required cooling

output (currently maximum 5000 rpm with vehicle stationary).

2. Working with air conditioner service station

GETth

211

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ The temperature of the air after the evaporator, the current air

conditioner compressor speed and the pressure of the refrig‐

erant on the high-pressure side are displayed as a measured

value from various control units depending on the vehicle (e.g.

operating and display unit, -E87- , -J255- , thermal manage‐

ment control unit - J1024- and air conditioning system control

unit - J301- ) ⇒ Vehicle diagnostic tester in “Guided Fault Find‐

ing” mode - air conditioner compressor and battery regulation.

♦ In the event of a very high cooling output (e.g. at high outside

temperatures and high fresh air blower speed), the air condi‐

tioner compressor is initially incapable of changing the pres‐

sure on the low pressure side to the required level (e.g. for a

certain period after switching on the air conditioning system).

The air conditioner compressor is not activated with the max.

specified (of approx. 8500 rpm), if the vehicle stands still or

drives slowly (up to a vehicle speed of 45 km/h). The air con‐

ditioner compressor speed is then limited to 5000 rpm. The

maximum permissible air conditioner compressor speed limit

is not lifted until a vehicle speed greater than approx. 45 km/

h is reached. The output (delivery rate) of the air conditioner

compressor at an air conditioner compressor speed of

5000 rpm, a high ambient temperature and high fresh air blow‐

er speed (unfavourable ambient conditions) is initially no lon‐

ger sufficient to bring the pressure on the low pressure side

down to the specified value. To check the regulating behaviour

of the air conditioner compressor under these conditions, e.g.

only actuate the fresh air blower with approx. 40% of the max‐

imum voltage and check the pressures at reduced fresh air

blower speed ⇒ Vehicle diagnostic tester in “Guided Fault

Finding” mode - air conditioning system and battery regulation

and ⇒ Heating, air conditioning; Rep. gr. 00 ; Repair instruc‐

lk

tions; Checking cooling output (vehicle-specific workshop

manual).

♦ If the demand on the cooling output is low (e.g. at an ambient

temperature of 20°C and a low fresh air blower speed), pres‐

sure on the high pressure side may only increase up to a value

of 6 to 7 bar (the energy exchange is low, the refrigerant is

cooled down quickly in the condenser). To check the regulat‐

ing behaviour and the pressures in the refrigerant circuit under

these conditions, e.g. actuate the fresh air blower with maxi‐

mum voltage, set the air conditioning system to maximum

heating output and activate air recirculation ⇒ Vehicle diag‐

nostic tester in “Guided Fault Finding” mode - air conditioning

system and ⇒ Heating, air conditioning; Rep. gr. 00 ; Repair

instructions; Checking cooling output (vehicle-specific work‐

shop manual).

♦ 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 specified speed of the air conditioner compressor is dis‐

played by various control units depending on the vehicle (e.g.

operating and display unit, -E87- , -J255- and air conditioning

system control unit - J301- ⇒ Vehicle diagnostic tester) in

“Guided Fault Finding” mode - air conditioning system.

♦ The high-pressure measured by various senders (e.g. high-

pressure sender - G65- , pressure sender for refrigerant circuit

- G805- or refrigerant pressure and temperature sender -

G395- ) is displayed as a measured value depending on the

vehicle (e.g. by -E87- , -J301- , thermal management control

unit - J1024- or -J255- ) ⇒ Vehicle diagnostic tester in “Guided

Fault Finding” mode - air conditioner compressor.

212

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

♦ The low pressure adjusts itself depending on the speed of the

air conditioner compressor and the regulating characteristic of

the expansion valve within the performance band of the air

conditioner compressor in the tolerance range (1.5 to 2.3 over‐

pressure).

♦ For this test, the specified speed of the air conditioner com‐

pressor must be greater than 1500 rpm ⇒ Vehicle diagnostic

tester in “Guided Fault Finding” mode - air conditioning sys‐

tem.

♦ For the “maximum cooling output” setting, the specified speed

of the air conditioner compressor is regulated at approx. 4000

to 5000 rpm. This value is vehicle-specific and is displayed as

a measured value by the respective control unit (e.g. operating

and display unit, -E87- , -J255- or thermal management control

unit - J1024- ⇒ Vehicle diagnostic tester) in “Guided Fault

Finding” mode - air conditioning system and battery regulation.

♦ Absolute pressure means that 0 bar corresponds to an abso‐

lute vacuum. The normal ambient pressure corresponds to 1

bar absolute. On the scales of most pressure gauges, 0 bar

corresponds to an absolute pressure of 1 bar (can be seen

from -1 bar mark below 0) ⇒ Vehicle diagnostic tester in “Gui‐

ded Fault Finding” mode - air conditioning system.

♦ If, on a vehicle with 2 evaporators (one in the heater and air

conditioner unit and one for battery cooling), the temperature

lk

measured at one evaporator meets the specification or falls

below the specification, while on the other evaporator, how‐

ever, the requisite specification is not reached, regulation

works as follows: the respective control unit (e.g. battery reg‐

ulation control unit or thermal management control unit )

makes the electrical air conditioner compressor run at a higher

speed via additional controls units (e.g. power and control

electronics for electric drive and control unit for air conditioning

compressor ) (which results in the cooling output of the air

conditioning system rising and pressure on the low pressure

side falling along with the evaporator temperature). If the spec‐

ification then falls below the minimum level at one evaporator,

the respective control unit (e.g. battery regulation control unit )

actuates the shut-off valves (e.g. refrigerant shut-off valve 1

or refrigerant shut-off valve 2 ) in such a way that the evapo‐

rator that is too cold no longer has refrigerant flowing through

it ⇒ Vehicle diagnostic tester in “Guided Fault Finding” mode

- air conditioning system and battery regulation as well as ⇒

Heating, air conditioning; Rep. gr. 00 ; Repair instructions;

Checking cooling output (vehicle-specific workshop manual)

and ⇒ Heating, air conditioning; Rep. gr. 87 ; Overview of

fitting locations - air conditioning system (vehicle-specific

workshop manual).

♦ Since the output of the evaporator in the battery cooling mod‐

ule is considerably lower than the output of the evaporator in

the heating and air conditioning unit, the requisite specified

temperature in the battery cooling module may still be reached

if there is insufficient refrigerant in the circuit but the specified

temperature in the evaporator of the heating and air condi‐

tioning unit will no longer be reached (even though the air

conditioner compressor is actuated at a higher speed) ⇒

Heating, air conditioning; Rep. gr. 00 ; Repair instructions;

Checking cooling output (vehicle-specific workshop manual)

and ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant cir‐

cuit (vehicle-specific workshop manual).

2. Working with air conditioner service station

GETth

213

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Possible deviations from specification,

cause and rectification

♦ The requisite cooling output in the evap‐ ⇒ page 216

orator of the heating and air conditioning

unit (and in the evaporator for the battery

cooling module) is not reached.

♦ High pressure remains constant or in‐

creases only slightly (above the pressure

measured when the engine is stopped).

♦ High pressure drops quickly to the spec‐

ification or lower.

♦ The requisite cooling output in the evap‐ ⇒ page 218

orator in the heating and air conditioning

unit (and in the evaporator for battery

cooling) is reached initially. However, af‐

ter a while or after an extended period of

lk

operation, the cooling output is no longer

adequate.

♦ The high pressure and the low pressure

are normal to start with

♦ After some time, the high pressure rises

above the specification, the low pressure

still equates to the specification or it

drops below the specification.

♦ The requisite cooling output in the evap‐ ⇒ page 220

orator of the heating and air conditioning

unit (and in the evaporator for the battery

cooling module) is not reached.

♦ The high pressure equates to the speci‐

fication

♦ The low pressure is too low (lower than

the specification)

♦ The air conditioner compressor is noisy ⇒ page 222

(especially immediately after being

switched on),

♦ The requisite cooling output in the evap‐

orator of the heating and air conditioning

unit and / or in the evaporator for battery

cooling is not reached.

♦ High pressure normal or too high

♦ Low pressure too high (specification is

not reached)

♦ The requisite cooling output in the evap‐ ⇒ page 224

orator of the heating and air conditioning

unit (and in the evaporator for the battery

cooling module) is not reached.

♦ High pressure and low pressure normal

(equate to specification)

214

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Possible deviations from specification,

cause and rectification

♦ The requisite cooling output in the evap‐ ⇒ page 226

orator of the heating and air conditioning

unit (and in the evaporator for the battery

cooling module) is not reached.

♦ The high pressure equates to the speci‐

fication

♦ The low pressure equates to the specifi‐

cation or is too low

♦ The requisite cooling output in the evap‐ ⇒ page 227

orator of the heating and air conditioning

unit (and in the evaporator for the battery

lk

cooling module) is not reached.

♦ The high pressure equates to the speci‐

fication

♦ Low pressure drops quickly to the spec‐

ification or lower.

♦ The requisite cooling output in the evap‐ ⇒ page 228

orator of the heating and air conditioning

unit (and in the evaporator for the battery

cooling module) is not reached.

♦ The requisite cooling output is then not

reached at the evaporator in the heater

and air conditioning unit (the cooling out‐

put at the evaporator in the battery cool‐

ing module is OK).

♦ High pressure increases only slightly

(above the pressure measured when the

engine is stationary) or equates to the

specification.

♦ Low pressure drops (possibly quickly) to

the specification or lower.

♦ The requisite cooling output in the evap‐ ⇒ page 229

orator of the heating and air conditioning

unit (and in the evaporator for the battery

cooling module) is not reached.

♦ The high pressure increases beyond the

specified value

♦ Low pressure drops quickly to the spec‐

ification or lower.

♦ The requisite cooling output is then not ⇒ page 232

reached at the evaporator for battery

cooling (the cooling output at the evapo‐

rator in the heater and air conditioning

unit is OK).

♦ High pressure equates to the specifica‐

tion or increases only slightly (above the

pressure measured when the engine is

stationary).

♦ Low pressure drops to the specification

or lower.

2. Working with air conditioner service station

GETth

215

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Possible deviations from specification,

cause and rectification

♦ The requisite cooling output in the evap‐ ⇒ page 233

lk

orator of the heating and air conditioning

unit (and in the evaporator for the battery

cooling module) is not reached.

♦ High pressure does not increase or only

marginally above the pressure with the

engine stationary

♦ The low pressure does not drop or only

marginally

Possible deviation from specification during pressure test

♦ The requisite cooling output in the evaporator of the heating and air conditioning unit (and in the evaporator

for the battery cooling module) is not reached.

♦ High pressure remains constant or increases only slightly (above the pressure measured when the air

conditioner compressor is stationary).

♦ High pressure drops quickly to the specification or lower.

Possible causes for deviation from specification and rectification

♦ There is too little refrigerant in the refrigerant circuit.

– Extract refrigerant from the refrigerant circuit ⇒ “2.4 Emptying refrigerant circuit”, page 137 .

– If the extracted refrigerant volume is considerably less than the specified fill volume (more than 100 g less)

⇒ Heating, air conditioning; Rep. gr. 00 ; Technical data (vehicle-specific workshop manual), search for

the leak and rectify the cause ⇒ “1.4 Investigating leaks”, page 68

– The extracted refrigerant volume approximately equates to the prescribed fill volume, check actuation of

the air conditioner compressor and the installed shut-off valves. If no fault is found, renew the expansion

valve for the evaporator in the heater and air conditioning unit ⇒ Heating, air conditioning; Rep. gr. 87 ;

Refrigerant circuit (vehicle-specific workshop manual)

♦ Actuation of air conditioner compressor (and if fitted refrigerant shut-off valve 1 and refrigerant shut-off

valve 2 ) faulty ⇒ Vehicle diagnostic tester in “Guided Fault Finding” mode - air conditioning system and

battery regulation, ⇒ Heating, air conditioning; Rep. gr. 00 ; Repair instructions; Checking cooling output

(vehicle-specific workshop manual), ⇒ Heating, air conditioning; Rep. gr. 87 ; Overview of fitting locations

- air conditioning system (vehicle-specific workshop manual) and ⇒ Heating, air conditioning; Rep. gr. 87 ;

Air conditioner compressor (vehicle-specific workshop manual).

– Check actuation and the function of the air conditioner compressor (and if fitted the shut-off valves, e.g.

refrigerant shut-off valve 1 , refrigerant shut-off valve 2 ) and repair if necessary ⇒ Vehicle diagnostic tester

in “Guided Fault Finding” mode - air conditioning system and battery regulation. If this is OK, extract the

refrigerant from the refrigerant circuit ⇒ “2.4 Emptying refrigerant circuit”, page 137 .

♦ The expansion valve for the evaporator in the heater and air conditioning unit is defective and must be

renewed ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific workshop manual).

♦ One of the refrigerant shut-off valves (if fitted) is defective (closed). Check the function and renew if nec‐

essary ⇒ Vehicle diagnostic tester in “Guided Fault Finding” mode - air conditioning system and battery

regulation and ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit; System overview - refrigerant

circuit

♦ Bottle-neck or blockage in refrigerant circuit (e.g. in refrigerant line between service connection on “low

pressure side” and air conditioner compressor) ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific workshop manual).

– If there is a blockage, clean the refrigerant circuit (flush with R1234yf refrigerant)

⇒ “1.6 Cleaning refrigerant circuit”, page 92 .

– If a hose or pipe is kinked or crushed, renew this component ⇒ Heating, air conditioning; Rep. gr. 87 ;

Refrigerant circuit (vehicle-specific workshop manual).

♦ The expansion valve for the evaporator in the heater and air conditioning unit is defective and must be

renewed ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific workshop manual).

♦ A refrigerant shut-off valve is defective (closed). Check the function and renew ⇒ Vehicle diagnostic tester

in “Guided Fault Finding” mode - air conditioning system and battery regulation and ⇒ Heating, air condi‐

tioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific workshop manual).

216

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Possible deviation from specification during pressure test

Final measures

– Recharge the refrigerant circuit ⇒ “2.6 Charging refrigerant circuit”, page 146

– Repeat test

⇒ “2.14.5 Checking pressures with air conditioning system switched on - vehicles with electrical air condi‐

tioning compressor”, page 205

lk

2. Working with air conditioner service station

GETth

217

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

lk

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ If, with this problem, no fault is found during diagnosis, check

the refrigerant circuit for a bottle-neck or blockage (a bottle-

neck or blockage in the refrigerant circuit can also lead to one

of these complaints). If nothing is found here either, clean the

refrigerant circuit (flush with R1234yf refrigerant)

⇒ “1.6 Cleaning refrigerant circuit”, page 92 .

♦ Check the measured values of the evaporator output temper‐

ature sender - G263- and, if fitted, temperature sensor before

evaporator for hybrid battery and temperature sensor after

evaporator for hybrid battery as well as actuation of air condi‐

tioner compressor via the respective control unit ⇒ Vehicle

diagnostic tester in “Guided Fault Finding” mode - air condi‐

tioning system and battery regulation.

♦ If there is a fault in the measured value of -G263- , temperature

sensor before evaporator for hybrid battery or temperature

sensor after evaporator for hybrid battery (depending on the

vehicle ⇒ Vehicle diagnostic tester in “Guided Fault Finding” -

air conditioning system and battery regulation), problems may

also be encountered in the cooling output or the evaporator

could ice up.

♦ In the event of a fault in a temperature sensor, the evaporator

may ice up even though the correct quantity of refrigerant is

present in the refrigerant circuit.

♦ If, after repeating the test when the expansion valve has been

renewed, the air conditioning system is not operating correctly,

clean the refrigerant circuit (flush with R1234yf refrigerant)

⇒ “1.6 Cleaning refrigerant circuit”, page 92 . Then renew the

air conditioner compressor and desiccant cartridge (or reser‐

voir/receiver) ⇒ Heating, air conditioning; Rep. gr. 87 ; Re‐

frigerant circuit (vehicle-specific workshop manual).

♦ If the expansion valve on the evaporator in the heater and air

conditioning unit or the shut-off valve is defective (always

closed or does not open sufficiently), the air conditioner com‐

pressor is actuated at the maximum output and low pressure

drops to the specification or lower (the air conditioner com‐

pressor draws in refrigerant from the low pressure side). Since

no refrigerant can flow through the expansion valve, however,

the cooling output is not reached and the high pressure may

also not increase or only increase slightly owing to there being

no energy exchange ⇒ Vehicle diagnostic tester in “Guided

Fault Finding” mode - air conditioning system and battery reg‐

ulation and ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrig‐

erant circuit (vehicle-specific workshop manual).

♦ The evaporator in the heater and air conditioning unit has a

considerably higher output than the evaporator for battery

cooling. Depending on the way the drive battery - A2- is cooled

(depending on the vehicle ⇒ Vehicle diagnostic tester in “Gui‐

ded Fault Finding” - air conditioning system and battery regu‐

lation), the refrigerant shut-off valve 2 on the expansion valve

in the battery cooling module is currently only actuated from a

certain battery temperature by the respective control unit (e.g.

by battery regulation control unit ) so that the power consumed

by the evaporator for battery cooling is not or barely increased

⇒ Vehicle diagnostic tester in “Guided Fault Finding” mode -

air conditioning system and battery regulation as well as ⇒

Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (ve‐

hicle-specific workshop manual).

218

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Possible deviation from specification during pressure test

♦ The requisite cooling output in the evaporator in the heating and air conditioning unit (and in the evaporator

for battery cooling) is reached initially. However, after a while or after an extended period of operation, the

cooling output is no longer adequate.

♦ The high pressure and the low pressure are normal to start with

♦ After some time, the high pressure rises above the specification, the low pressure still equates to the

specification or it drops below the specification.

Possible causes for deviation from specification and rectification

♦ Radiator, condenser contaminated or actuation of the radiator is not OK

– Check actuation of the radiator fan and repair if necessary ⇒ Vehicle diagnostic tester in “Guided Fault

Finding” mode - air conditioning system.

– Check condenser for contamination and clean if necessary ⇒ Heating, air conditioning; Rep. gr. 87 ;

Refrigerant circuit (vehicle-specific workshop manual) and ⇒ Engine, mechanicals; Rep. gr. 19 ; Radiator/

radiator fan .

♦ Actuation or the function of the air conditioner compressor (or, if fitted, the refrigerant shut-off valve 1 or

refrigerant shut-off valve 2 ) is faulty.

♦ Moisture in refrigerant circuit

– Check the actuation of the air conditioner compressor (and if fitted the refrigerant shut-off valve 1 and

refrigerant shut-off valve 2 ) and check the measured value of the evaporator output temperature sender

- G263- ⇒ Vehicle diagnostic tester in “Guided Fault Finding” mode.

– If actuation of the air conditioner compressor (and, if fitted, the refrigerant shut-off valve 1 and refrigerant

shut-off valve 2 ) as well as the measured value of -G263- are OK, extract the refrigerant from the refrigerant

circuit ⇒ “2.4 Emptying refrigerant circuit”, page 137 .

♦ Too much refrigerant in the refrigerant circuit