Get Air conditioning system Refrigerant circuit -> 1.2 General description - components of refrigerant circuit Guide for Volkswagen Sharan VAN Second Generation (2010-2023)

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

1.2

General description - components of re‐

frigerancircui

⇒ “1.2.1 Layouand function of refrigerancircuit”, page 36

⇒ “1.2.2 Mechanical air conditioner compressor”, page 38

⇒ “1.2.3 Electrical air conditioner compressor for hybrid vehicles”,

page 40

⇒ “1.2.4 Condenser”, page 43

⇒ “1.2.5 Evaporator”, page 43

⇒ “1.2.6 Reservoir”, page 44

⇒ “1.2.7 Heaexchanger for heapump mode”, page 45

⇒ “1.2.8 Liquid receiver”, page 45

⇒ “1.2.9 Restrictor”, page 46

⇒ “1.2.10 Receiver”, page 47

⇒ “1.2.11 Expansion valve (with and withoushut-off valve)”, page

48

⇒ “1.2.12 Refrigeranshut-off valves”, page 50

⇒ “1.2.13 Refrigeranline with internal heaexchanger”,

page 51

⇒ “1.2.14 Quick release couplings of refrigeranlines”,

page 51

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⇒ “1.2.15 Seals”, page 52

⇒ “1.2.16 Pipes and hoses in refrigerancircuit”, page 52

⇒ “1.2.17 High-pressure safety valve”, page 53

⇒ “1.2.18 Non-return valves”, page 54

⇒ “1.2.19 Quick-release coupling connections in refrigerancir‐

cuit”, page 55

⇒ “1.2.20 Connections with valve for switches in refrigerancircui

”, page 59

⇒ “1.2.21 Pressure senders and switches in refrigerancircuit”,

page 59

⇒ “1.2.22 Refrigeranpressure and temperature sender”,

page 60

⇒ “1.2.23 Air conditioner compressor regulating valve N280 ”,

page 63

⇒ “1.2.24 Refrigerantemperature sender”, page 63

1.2.1

Layouand function of refrigerancircui

♦ Located on the high-pressure side are the condenser, receiver

and restrictor or expansion valve to separate the high-pres‐

sure side (HD) and low-pressure side (ND).

♦ High pressure is created by the restrictor or expansion valve

forming a constriction and causing the refrigeranto build up,

thus leading to increased pressure and temperature.

♦ Excessive pressure results if the circuiis filled with too much

refrigeranor refrigeranoil, or the condenser is dirty, the ra‐

diator fan is defective, there is a blockage in the system or

there is moisture in the refrigerancircui(causing the restrictor

or expansion valve to ice up).

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

♦ Located on the low-pressure side are the evaporator, the tem‐

perature sensor for the evaporator and the air conditioner

compressor thaacts as the separation between the high-

pressure (HD) and low-pressure (ND) gas sides.

♦ A loss of pressure in the system can be due to loss of refrig‐

erant, restrictor or expansion valve defective or blocked, de‐

fective air conditioner compressor or an iced-up evaporator.

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1. Refrigerancircui

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

1.2.2

Mechanical air conditioner compressor

The air conditioner compressor is driven by a poly V-bel-B- or a

shafby the engine.

Air conditioner compressor with air conditioning system magnetic

clutch - N25- :

An electromagnetic clutch -A- attached to the air conditioner com‐

pressor provides power transfer between pulley -B- and com‐

pressor crankshafwhen the air conditioning is switched on.

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An overload protection device attached to the clutch plate or fitted

in the solenoid of the air conditioner compressor triggers if there

is resistance in the air conditioner compressor (sluggish move‐

ment), protecting the beldrive or the drive uniagainsoverload.

Note

♦ To ensure thathe air conditioner compressor is nodamaged

if the refrigerancircuiis empty, the air conditioner compres‐

sor regulating valve - N280- and, under certain circumstances,

the air conditioning system magnetic clutch - N25- are no lon‐

ger actuated (the air conditioner compressor only runs aidle

with the engine if -N25- is actuated).

♦ An air conditioner compressor with -N25- (withou-N280- ) is

noactuated if the refrigerancircuiis empty and is therefore

nodriven.

Air conditioner compressor withouair conditioning system mag‐

netic clutch - N25- :

♦ An overload protection device attached to the pulley -B- or fit‐

ted in the drive uniof the air conditioner compressor triggers

if there is resistance in the air conditioner compressor (slug‐

gish movement), protecting the beldrive or the drive uni

againsoverload.

♦ An air conditioner compressor with air conditioner compressor

regulating valve - N280- (withou-N25- ) is switched over to

internal lubrication via a valve if the refrigerancircuiis empty.

Note

♦ On air conditioner compressors withouair conditioning sys‐

tem magnetic clutch - N25- , the engine may only be started

following complete assembly of the refrigerancircuit.

♦ To ensure thathe air conditioner compressor suffers no dam‐

age if the refrigerancircuiis empty, the air conditioner com‐

pressor regulating valve - N280- is no longer activated (the air

conditioner compressor idles with the engine).

All air conditioner compressors

The air conditioner compressor draws refrigerangas from the

evaporator, compresses iand sends ito the condenser.

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Rep. gr.87 - Air conditioning system

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

Note

♦ The air conditioner compressor contains refrigeranoil, which

can be mixed with R1234yf refrigeranaany temperature.

♦ The identification plate states the refrigeranfor which the air

conditioner compressor is suitable. A valve regulates the pres‐

sure on the low-pressure side within the specified range (con‐

trol characteristic) ⇒ Heating, air conditioning system; Rep.

gr. 87 ; Refrigerancircui.

lk

♦ Depending on the version of air conditioner compressor, dif‐

ferenrefrigeranoils are filled in the air conditioner compres‐

sor. Refrigeranoils thawere developed for R134a refrigeran

oil only, musnobe used for R1234yf refrigeran⇒ Heating,

air conditioning system; Rep. gr. 00 ; Technical data; Refrig‐

eranoil .

♦ Air conditioner compressors with or withouair conditioning

system magnetic clutch - N25- are currently actuated via an

air conditioner compressor regulating valve - N280- -C- exter‐

nally ⇒ Heating, air conditioning system; Rep. gr. 87 ; Re‐

frigerancircui.

♦ The identification plate states the refrigeranfor which the air

conditioner compressor is suitable. An air conditioner com‐

pressor regulating valve - N280- regulates the pressure on the

low-pressure side within the specified range (control charac‐

teristic) ⇒ Heating, air conditioning system; Rep. gr. 87 ;

Refrigerancircui.

♦ The air conditioner compressor regulating valve - N280- is ac‐

tuated externally ⇒ Vehicle diagnostic tester in “Guided Faul

Finding” in air conditioning system.

♦ The engine musnobe started in a vehicle with air conditioner

compressor buno air conditioner compressor magnetic clutch

- N25- if there is negative pressure in the refrigerancircui

(e.g. during evacuation) ⇒ page 129 .

♦ The engine may only be started in a vehicle with air conditioner

compressor buno air conditioner compressor magnetic clutch

- N25- when the refrigerancircuihas been completely as‐

sembled.

♦ To ensure thathe air conditioner compressor suffers no dam‐

age if the refrigerancircuiis empty, the air conditioner com‐

pressor regulating valve - N280- is no longer activated (the air

conditioner compressor idles with the engine) if the pressure

in the refrigerancircuiis too low (lower than approx. 2 bar).

♦ An air conditioner compressor with air conditioner compressor

regulating valve - N280- is switched over to internal lubrication

via a valve if the refrigerancircuiis empty.

♦ Depending on the version of air conditioner compressor, a

valve may be installed on the high-pressure side thaprevents

liquefied refrigeranflowing back into the air conditioner com‐

pressor after the air conditioning system is switched off. If an

air conditioner compressor with this valve is installed in a ve‐

hicle with a refrigerancircuiwith expansion valve, icould

take some time before the pressure on the high-pressure side

drops (the expansion valve is cold and the pressure on the

low-pressure side rises quickly after switching off, the expan‐

sion valve closes and refrigeranonly flows slowly on the low-

pressure side). If the air conditioner compressor is switched

on, the pressure on the low-pressure side drops, the expan‐

sion valve opens and refrigerancan flow on the low-pressure

side.

1. Refrigerancircui

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

♦ On an air conditioner compressor with electromagnetic clutch

-A- and regulating valve -C-, the electromagnetic clutch -A- is

usually only actuated if the regulating valve -C- is also actu‐

ated ⇒ Heating, air conditioning system; Rep. gr. 87 ; Refrig‐

erancircui.

1.2.3

Electrical air conditioner compressor for

hybrid vehicles

Vehicles with high-voltage system (hybrid vehicles)

If repair work in the vicinity of high-voltage components and ca‐

bles is necessary, inspechigh-voltage components and cables

for damage ⇒ page 4 ⇒ Electrical system; Rep. gr. 93 ; General

warnings for work on the high-voltage system .

If work on the components of the high-voltage system is neces‐

sary, ensure thathe high-voltage system is de-energised ⇒ Rep.

gr. 93 ; De-energising high-voltage system .

De-energise the high-voltage system and restarting the high-volt‐

age system ⇒ Rep. gr. 93 ; De-energising high-voltage system

– To minimise the number of automatic engine starts when the

vehicle's drive system is active (READY) during tesand

measuremenwork, charge the vehicle batteries e.g. with the

battery charger 60 A - VAS 5904- in battery standby mode ⇒

Electrical system - General information; Rep. gr. 27 ; Charging

battery and ⇒ Electrical system; Rep. gr. 93 ; General warn‐

ings for work on the high-voltage system .

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

– For testing and measuring work tharequires 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

parking brake, and arrange the tools needed so thathey can‐

nocome into contacwith moving components of the engine

and so thathey cannoeven come near to components tha

turn when the engine is running.

Electrical air conditioner compressor

NOTICE

Risk of irreparable damage to electrical air conditioner com‐

pressor from shorcircuit.

– Never touch the air conditioner compressor when switching

on the ignition or starting the drive machines.

♦ The air conditioner compressor draws refrigerangas from the

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evaporator, compresses iand sends ito the condenser.

♦ The electric motor of the air conditioner compressor is sup‐

plied with power e.g. from the power and control electronics

for electric drive - JX1- ⇒ Currenflow diagrams, Electrical faul

finding and Fitting locations.

♦ The control unifor air conditioner compressor - J842- inte‐

grated in the air conditioner compressor regulates the speed

and thereby the performance of the air conditioner compressor

( electrical air conditioner compressor - V470- ) according to

the requesreceived via the data bus ⇒ Vehicle diagnostic

tester in “Guided FaulFinding” function of air conditioning

system and battery control system

♦ There is no air conditioner compressor regulating valve -

N280- in the electrical air conditioner compressor.

♦ The bolting points of the air conditioner compressor and the

brackemusbe checked prior to installation. The contacsur‐

faces musbe free of dirt, rusand grease. Otherwise, repair

contacsurfaces using contacsurface cleaning se- VAS

6410- ⇒ Electrical system; General information; Rep. gr. 97 ;

Wiring harness and connector repair .

1. Refrigerancircui

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

Note

♦ If the air conditioner compressor control uni- J842- is defec‐

tive, the amounof refrigeranoil in the new air conditioner

compressor musbe adjusted. The refrigerancircuimusno

be cleaned (flushed) with R1234yf.

♦ The control unifor air conditioner compressor - J842- and the

electrical air conditioner compressor - V470- are one compo‐

nenand can currently nobe separated.

♦ There is no -N280- installed in the electrical air conditioner

compressor. The power of the air conditioner compressor is

regulated externally by the speed of the air conditioner com‐

pressor ⇒ Currenflow diagrams, Electrical faulfinding and

Fitting locations and ⇒ Vehicle diagnostic tester in “Guided

FaulFinding” mode - air conditioning system and battery reg‐

ulation.

♦ The electrical air conditioner compressor currently works in

the same way as a spiral or scroll-type charger (similar to a G-

Lader).

♦ The air conditioner compressor contains refrigeranoil, which

can be mixed with R1234yf refrigeranaany temperature.

♦ The identification plate states the refrigeranfor which the air

conditioner compressor is suitable.

♦ The integrated electronics regulate the performance of the air

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conditioner compressor via the speed (and thereby the pres‐

sure on the low-pressure side) within the specific tar range

(control characteristic).

♦ The engine should be started only when the refrigerancircui

has been fully assembled.

♦ The air conditioner compressor has an internal oil circuito

ensure thathe air conditioner compressor is nodamaged

when the refrigerancircuiis empty. This means thaapprox.

40 to 50 cm³of refrigeranoil remain in the air conditioner

compressor.

♦ Juslike the mechanical air conditioner compressor, the elec‐

trical air conditioner compressor has a pressure relief valve.

♦ On vehicles with battery cooling, electric and hybrid operation

is only possible with the air conditioning system charged and

no faults stored in connection with the air conditioning system

⇒ Vehicle diagnostic tester in “Guided FaulFinding” mode -

air conditioning system and battery regulation.

♦ Firsbring the electrical air conditioner compressor into oper‐

ation after installing the air conditioner compressor and charg‐

ing the refrigerancircuivia the “Compressor run-in” function

in basic settings. Should there be an accumulation of refriger‐

anoil in the compression chamber of the air conditioner

compressor before installation owing to unfavourable storage,

damage could be caused to the air conditioner compressor

⇒ Vehicle diagnostic tester in “Guided FaulFinding” mode -

air conditioning system and battery regulation.

♦ An electrically driven air conditioner compressor may only be

activated when the refrigerancircuiis charged. Running the

air conditioner compressor with the refrigerancircuiempty

could lead to compressor damage ⇒ Vehicle diagnostic tester

in “Guided FaulFinding” mode.

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

1.2.4

Condenser

♦ The condenser -A- transfers heafrom the compressed refrig‐

erangas into the surrounding air.

♦ When this happens, the refrigerangas condenses to liquid.

Note

♦ Depending on the design of the refrigerancircuit, the receiver

may be attached to the condenser or integrated in the con‐

denser ⇒ Heating, air conditioning system; Rep. gr. 87 ;

Refrigerancircui(vehicle-specific workshop manual) and ⇒

Electronic parts catalogue .

lk

♦ There are differenversions of the condenser; from the outside

these versions can only be identified by their parnumber.

Version -1- of the condenser is spliinto two sections (“two-

pass condenser”). Version -2- of the condenser is spliinto four

sections (“four-pass condenser”).

♦ This illustration shows a condenser with the receiver -C- at‐

tached.

♦ The gaseous refrigeranenters the condenser aconnection

-A-; the refrigeranis then cooled down in the condenser and

turns into liquid.

♦ The liquid refrigeranaccumulates in receiver -C- (with dryer)

and flows through the bottom cooling section to connection

-B-.

♦ The refrigerancapacity in a refrigerancircuimay differ de‐

pending on the design of the condenser (internal volume, flow,

etc.). Therefore, always ensure the version and allocation of

the condenser are correc⇒ Heating, air conditioning system;

Rep. gr. 00 ; Technical data (vehicle-specific workshop man‐

ual) and ⇒ Electronic parts catalogue .

1.2.5

Evaporator

There are differentypes of evaporator. Depending on the design

and function, the thermal energy thais needed to evaporate the

refrigeranis drawn from the air flowing through the system (e.g.

with the evaporator in heater and air conditioning unior in the

battery cooling module) or the coolanflowing through the system

(e.g. with the heaexchanger for the high-voltage battery) ⇒

Heating, air conditioning system; Rep. gr. 87 ; Refrigerancircuit;

System overview - refrigerancircui(vehicle-specific workshop

manual).

Note

The following describes 2 versions of the evaporator.

1. Refrigerancircui

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

Evaporator in heating and air conditioning system (or in the bat‐

tery cooling module)

♦ The liquid refrigeranevaporates in the pipelines of the evap‐

orator -A-. The hearequired to do this is drawn from the air

flowing over the evaporator fins -B-. The air cools down. The

refrigeranevaporates and is drawn into the air conditioning

system compressor carrying with ithe heaihas absorbed.

♦ A defined quantity of refrigeranis fed to the evaporator

through an expansion valve (restrictor). In systems with an

expansion valve the flow rate is regulated such thaonly gas‐

eous refrigeranemerges athe evaporator outlet.

♦ When R1234yf refrigeranwas introduced, the evaporators

were adapted to the refrigerant, hence the need to observe the

correcversion ⇒ Electronic parts catalogue .

Evaporator / heaexchanger for high-voltage battery (chiller)

The liquid refrigeranevaporates in the evaporator (heaex‐

changer). The hearequired to do this is drawn from the coolan

thaflows through the evaporator. The coolancools. The refrig‐

eranevaporates and is drawn into the air conditioner compressor

carrying with ithe heaihas absorbed.

A defined quantity of refrigeranis fed to the evaporator through

a restrictor (or an expansion valve) and a shut-off valve. The flow

rate of the coolan(or refrigerant) is regulated in such a way tha

only gaseous refrigeranescapes athe evaporator outle⇒

Heating, air conditioning; Rep. gr. 87 ; Refrigerancircuit; System

overview - refrigerancircui(vehicle-specific workshop manual).

1.2.6

Reservoir

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Note

This type of air conditioning system is currently only installed in

systems with a restrictor.

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♦ The reservoir collects the vaporised and gaseous mixture

coming from the evaporator to ensure the air conditioner com‐

lk

pressor receives only gaseous refrigerant. The vapour be‐

comes gaseous refrigerant.

♦ Refrigerant oil flowing in the circuidoes noremain in the res‐

ervoir because an oil extraction hole has been provided.

♦ Any moisture ingress into the refrigerancircuiduring assem‐

bly is trapped by a filter (desiccanbag) in the reservoir.

♦ Gaseous refrigeranwith oil is drawn in by the air conditioner

compressor.

Note

♦ Renew the reservoir if the refrigerancircuihas been open for

an extended period of time and moisture has entered or if re‐

quired to do so owing to a specific complain⇒ page 79 .

♦ Do noremove sealing plugs -A- and -B- until jusbefore in‐

stallation.

♦ A dryer kepin an unsealed reservoir is saturated with mois‐

ture after a shortime and cannobe used.

♦ When installing, observe arrow indicating direction of flow if

applicable.

1.2.7

Heaexchanger for heapump mode

The gaseous or vaporous refrigerancompressed by the air con‐

ditioning compressor is liquefied in the heaexchanger -A-. The

heathais given off in the process is picked-up by the coolan

flowing through the system ⇒ Heating, air conditioning; Rep. gr.

87 ; Refrigerancircuit; System overview - refrigerancircui.

1.2.8

Liquid receiver

In certain operating conditions (e.g. in heapump mode), the re‐

ceiver (e.g. on the condenser) is nointegrated in the refrigeran

circuit. The receiver -B- collects the refrigerant, temporarily stores

any excess should a certain amounof refrigerannobe required

and then feeds iin a steady flow to the expansion valve (in fron

of the evaporator in the heater and air conditioning unit) or to the

heaexchanger in the coolancircuiof the high voltage system

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerancircuit; Sys‐

tem overview - refrigerancircui.

1. Refrigerancircui

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1.2.9

Restrictor

Restrictor in fronof evaporator

Note

Currently, there is no air conditioning system with a restrictor in‐

stalled in fronof the evaporator.

lk

♦ The restrictor creates a constriction. This restriction limits the

flow, separating the high pressure and low pressure sides in

the refrigerancircuit. Upstream of the restrictor, the refriger‐

anis warm due to the high pressure. Downstream of the

restrictor, the refrigeranis cold due to the low pressure. Up‐

stream of the constriction is a strainer to catch dirand down‐

stream of the constriction is a strainer to atomise the

refrigeranbefore ienters the evaporator.

Note

♦ Arrow -A- on the restrictor points to the evaporator.

♦ Renew every time the refrigerancircuiis opened.

♦ Note differenversions; refer to the various customer service

information ⇒ Electronic parts catalogue .

Restrictor in fronof heaexchanger for high-voltage battery (chill‐

er)

The restrictor creates a constriction. This restriction limits the flow,

separating the high pressure and low pressure sides in the re‐

frigerancircuit. Upstream of the restrictor, the refrigeranis warm

due to the high pressure. Downstream of the restrictor, the refrig‐

eranis cold due to the low pressure.

Note

♦ The illustration shows a refrigeranline -A- with a permanently

installed restrictor -B- (withoustrainer).

♦ The diameter of the shown restrictor hole -B- is

approx. 0.7 mm. Depending on the refrigeranline version, this

restrictor is permanently installed or ican be removed. For the

removable version a strainer may be fitted to preventhe re‐

strictor hole from being blocked by suspended particles.

♦ Check for soiling before installing and clean or renew as nec‐

essary.

♦ Observe differenversions.

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1.2.10

Receiver

♦ The receiver -B- collects the liquid droplets and directs them

in a continuous stream to the expansion valve. Any moisture

thahas entered the refrigerancircuiduring assembly is col‐

lected by a dryer -D- in the receiver -B-.

♦ Depending on the layouof the refrigerancircuiand the ver‐

sion of condenser -A-, the receiver -B- may be installed on the

condenser -A- or (integrated) in the condenser -A- ⇒ Heating,

air conditioning; Rep. gr. 87 ; Refrigerancircui(vehicle-spe‐

cific workshop manual) and ⇒ Electronic parts catalogue .

♦ Installed in the receiver -B- is a dryer (e.g. desiccanbag -D-)

and strainer -F- (thafilters ousmaller contaminants).

Note

♦ The receiver -B- comes in differenversions and differende‐

signs ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigeran

circui(vehicle-specific workshop manual) and ⇒ Electronic

parts catalogue .

♦ Renew the receiver -B- and plastic bol(with seals) -C-, des‐

iccancartridge -D-, filter carrier -E- and strainer -F- if the

refrigerancircuiwas open for an extended period of time and

moisture has been absorbed, or if required to do so owing to

a specific complain⇒ page 79 .

♦ Do noremove the sealing plugs of a receiver until immediately

prior to installation as a desiccanbag in a non-sealed reser‐

voir will become saturated with moisture and become unusa‐

ble.

♦ The desiccancartridge comes in an air-tightransporbag,

which should remain sealed for as long as possible. Do no

open the transporbag until immediately prior to inserting the

desiccancartridge -D- in the receiver -B- of the condenser.

After the transporbag has been opened, the desiccancar‐

tridge will become saturated with moisture within a shortime

and is then unusable.

♦ When installing, observe arrow indicating direction of flow if

applicable.

♦ The procedure to adopin the evenof a complaindiffers de‐

pending on the type of receiver/desiccancartridge. If the

receiver is installed on the condenser, for example, ican be

renewed completely with the desiccancartridge. If the receiv‐

er is integrated in the condenser, for example, the desiccan

cartridge and an additional filter elemen(if one is fitted) can

be replaced individually on mosversions. If the receiver is

integrated in the condenser and iis nopossible to replace

the receiver/desiccancartridge separately, imay be neces‐

sary to replace the entire condenser ⇒ Heating, air condition‐

ing; Rep. gr. 87 ; Refrigerancircui(vehicle-specific workshop

manual) and ⇒ Electronic parts catalogue .

♦ Depending on the layouof the refrigerancircui(with desic‐

canbag or desiccancartridge), the receiver may also be

integrated in the refrigerancircui(ineed noalways be in‐

stalled on or in the condenser) ⇒ Heating, air conditioning;

Rep. gr. 87 ; Refrigerancircui(vehicle-specific workshop

manual) and ⇒ Electronic parts catalogue .

1. Refrigerancircui

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1.2.11

Expansion valve (with and withoushut-

off valve)

Expansion valve withoushut-off function

The expansion valve -A- atomises incoming refrigeranand reg‐

ulates the flow so that, depending on the heatransport, the

vapour does nobecome a gas until ireaches the outleof the

evaporator.

Note

♦ When R1234yf refrigeranwas introduced, the expansion

valves were adapted to the refrigeran(differencharacteris‐

tics), hence the need to observe the correcversion ⇒ Elec‐

tronic parts catalogue .

♦ Differenversions of expansion valve due to differencharac‐

teristics thaare matched to the relevanrefrigerancircui⇒

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

hicle-specific workshop manual) and ⇒ Electronic parts cata‐

lk

logue .

♦ When renewing the expansion valve, make sure thathe par

number is correc⇒ Electronic parts catalogue .

♦ Depending on the version of air conditioner compressor, a

valve may be installed on the high-pressure side thaprevents

liquefied refrigeranflowing back into the air conditioner com‐

pressor after the air conditioning system is switched off. If an

air conditioner compressor with this valve is installed in a ve‐

hicle with a refrigerancircuiwith expansion valve, icould

take some time before the pressure on the high-pressure side

drops (the expansion valve is cold and the pressure on the

low-pressure side rises quickly after switching off, the expan‐

sion valve closes and refrigeranonly flows slowly on the low-

pressure side). If the air conditioner compressor is switched

on, the pressure on the low-pressure side drops, the expan‐

sion valve opens and refrigerancan flow on the low-pressure

side.

Expansion valve with refrigeranshut-off valve

Note

Shut-off valves come in differenversions, with differenfunctions

and differendesignations ⇒ Heating, air conditioning; Rep. gr.

87 ; Refrigerancircui(vehicle-specific workshop manual).

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♦ The expansion valve -A- with shut-off valve -B- atomises the

incoming refrigeranand regulates the flow rate of the refrig‐

eranto the evaporator in the battery cooling module of the

hybrid battery uni- AX1- in such a way that, depending on the

heatransport, the vapour does nobecome a gas until irea‐

ches the outleof the evaporator.

♦ If the shut-off valve -B- is actuated by the electronics, iis open

and allows refrigeranto flow through to the expansion valve

-A-.

♦ If the shut-off valve -B- is open, the expansion valve -A- allows

refrigeranto flow through to the evaporator or heaexchanger

based on its control characteristic ⇒ Heating, air conditioning;

Rep. gr. 87 ; Refrigerancircui.

♦ The solenoid -B- attached to the expansion valve -A- is actu‐

ated by differencontrol units depending on the vehicle ⇒ Cur‐

renflow diagrams, Electrical faulfinding and Fitting locations

and ⇒ Vehicle diagnostic tester in “Guided FaulFinding”

mode.

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

conditioner uniand one in the battery cooling module, e.g. the

Audi Q5 Hybrid), the temperature measured aone evaporator

meets the specification or falls below the specification, while

on the other evaporator however the requisite specification is

noreached, regulation works as follows: the battery regula‐

lk

tion control uni- J840- makes the electrical air conditioner

compressor run aa higher speed via the power and control

electronics for electric drive - JX1- and the control unifor air

conditioning compressor - J842- (which results in the cooling

outpuof the air conditioning system rising and pressure on

the low pressure side falling along with the evaporator tem‐

perature). If, as a result, the temperature aone evaporator

falls below the specified level, -J840- actuates refrigeranshut-

off valve 1 for hybrid battery - N516- or refrigeranshut-off

valve 2 for hybrid battery - N517- in such a way thathe evap‐

orator - which is too cold - no longer has refrigeranflowing

through i⇒ Vehicle diagnostic tester in “Guided FaulFinding”

mode.

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1.2.12

Refrigeranshut-off valves

Shut-off valves with 2 switch statuses (open or closed)

♦ Shut-off valves come in differenversions, with differenfunc‐

tions and differendesignations ⇒ Heating, air conditioning;

Rep. gr. 87 ; Refrigerancircui.

♦ If the shut-off valve -A- is noactuated by the electronics, iis

open and allows refrigeranto flow through.

♦ The shut-off valve -A- is installed on vehicles with high-voltage

system, for example. Iis actuated when no climate control is

wanted for the passenger compartmenbubattery cooling is

required for the hybrid battery uni- AX1- .

♦ Note the arrow -B- on the shut-off valve -A-, which shows the

direction of refrigeranflow (from condenser to evaporator in

the heater and air conditioning unit).

♦ The solenoid -C- attached to the shut-off valve -A- is actuated

by differencontrol units depending on the vehicle ⇒ Curren

flow diagrams, Electrical faulfinding and Fitting locations and

⇒ Vehicle diagnostic tester in “Guided FaulFinding” mode -

air conditioning system and battery regulation.

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

conditioner uniand one in the battery cooling module, e.g. the

Audi Q5 Hybrid), the temperature measured aone evaporator

meets the specification or falls below the specification, while

on the other evaporator however the requisite specification is

noreached, regulation works as follows: the respective con‐

trol unimakes the electrical air conditioner compressor run a

a higher speed (which results in the cooling outpuof the air

conditioning system rising and pressure on the low pressure

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

perature aan evaporator then falls below the specified level,

the respective control uniactuates the shut-off valve in such

lk

a way thathe evaporator thais too cold no longer has refrig‐

eranflowing through i⇒ Heating, air conditioning; Rep. gr.

87 ; Refrigerancircuiand ⇒ Vehicle diagnostic tester in “Gui‐

ded FaulFinding” mode.

Shut-off valves regulated via characteristic curves

♦ The shut-off valve -A- is actuated via an incremental motor

-B- by the respective control uniwith characteristic curves

(open or closed).

♦ If the shut-off valve acts as a control valve (e.g. refrigeran

expansion valve 1 - N636- as is the case with the Audi Q7), i

is only opened enough to allow the temperature sefor the hea

exchanger to be reached ⇒ Heating, air conditioning; Rep. gr.

87 ; Refrigerancircui.

♦ Shut-off valves actuated via incremental motors do nohave

a defined resposition. For this reason, they have to be seto

a certain position (open or closed) before work on the refrig‐

erancircuiis performed ⇒ Heating, air conditioning; Rep. gr.

87 ; Refrigerancircui.

♦ Depending on layouof the refrigerancircuithere could be a

cluster of shut-off valves forming a valve block (e.g. on the e-

Golf or Audi Q7 e-tron) ⇒ Heating, air conditioning; Rep. gr.

87 ; Refrigerancircui.

♦ The incremental motor is programmed and actuated via data

lines (LIN-Bus) by the respective control uniin relation to its

installation location ⇒ Heating, air conditioning; Rep. gr. 87 ;

Refrigerancircuiand ⇒ Vehicle diagnostic tester in “Guided

FaulFinding” mode.

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1.2.13

Refrigeranline with internal heaex‐

changer

♦ In this refrigeranline, the warm liquid refrigeranflowing on

the high pressure side supplies energy to the cold refrigeran

gas or vapour flowing on the low pressure side, thus enhanc‐

ing the efficiency of the air conditioner.

Note

This illustration shows a refrigeranline with inner heaexchanger

as fitted e.g. on the Golf 7, Audi A4 2008 > and Audi A5 Coupé

2008 > ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigeran

circui.

A - Refrigeranline with internal heaexchanger

B - Channels in the refrigeranline along which holiquid refrig‐

eranflows to the evaporator (high pressure side of refrigeran

circuit).

C - Channel in the refrigeranline through which the cold gaseous

or vaporous refrigeranflows to the air conditioner compressor

(low pressure side of refrigerancircuit).

1.2.14

Quick release couplings of refrigeran

lines

Note

♦ This illustration shows the quick-release couplings with a re‐

frigeranline with internal heaexchanger as fitted e.g. on the

Audi A4 2008 > and the Audi A5 Coupé 2008 > ⇒ Heating, air

conditioning; Rep. gr. 87 ; Refrigerancircui(vehicle-specific

workshop manual).

♦ Removal of the refrigeranline -D- involves opening the re‐

taining ring -A- e.g. with the refrigeranline release tool ( re‐

lease tool - T40149- or removal tool - T40232- ) ⇒ Heating,

air conditioning; Rep. gr. 87 ; Refrigerancircui(vehicle-spe‐

cific workshop manual).

♦ After removing the respective refrigeranline, the quick re‐

lease couplings -B- and -G- are to be renewed along with the

associated supporring -E- or -H- and the associated seal

-F- or -J- ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigeran

circui(vehicle-specific workshop manual) and ⇒ Electronic

parts catalogue .

A - Retaining ring (in quick release coupling on high pressure

side)

B - Quick release coupling with retaining ring “high pressure side”

C - Refrigeranline with internal heaexchanger

D - Refrigeranline “high pressure side”

E - Supporring “high pressure side”

F - Seal “high pressure side”

G - Quick release coupling with retaining ring “low pressure side”

H - Supporring “low pressure side”

J - Seal “low pressure side”

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Note

♦ The quick release couplings come in differenversions -A- and

-D-. On both versions of these quick release couplings, the

refrigeranlines -C- can be released and removed in the same

way, e.g. with refrigeranline release tool -T40149/1- ⇒ Heat‐

ing, air conditioning; Rep. gr. 87 ; Refrigerancircui(vehicle-

specific workshop manual).

♦ For quick release coupling version -A-, the control pins -B- be‐

come visible after installing the refrigeranline -C- once the

engaged refrigeranline -C- is pulled in the direction of arrow.

♦ For quick release coupling version -D-, the refrigeranline

-C- is installed in the same way as quick release coupling

-A-. When the refrigeranline -C- on this version is pulled in

the direction of arrow following assembly, the snap ring -E-

protrudes from the quick release coupling -D-, thereby indi‐

cating thathe retaining ring -F- is completely engaged with

the refrigeranline -C-. The snap ring -E- musthen be re‐

moved from the refrigeranline -C-.

1.2.15

Seals

♦ These seals seal the connection points between the individual

components of the refrigerancircui

⇒ “3.2 Refrigerancircuiseals”, page 8 .

lk

1.2.16

Pipes and hoses in refrigerancircui

♦ In its pure state, R1234yf refrigeranis chemically stable and

has no corrosive effecon e.g. iron, aluminium and specially

developed plastics thaare suitable for this purpose. A mixture

of refrigeranoil and R1234yf refrigerancan affeccertain

metals (e.g. alloys with copper) and affecor degrade certain

hose materials and plastics. Therefore, use only genuine re‐

placemenparts ⇒ Electronic parts catalogue .

♦ Only use components thaare resistanto R1234yf refrigeran

and its associated refrigeranoils. Do nouse components

(such as seals and hoses, which are made of plastic) tha

cannobe clearly allocated ⇒ Electronic parts catalogue .

♦ The pipes and hoses are held toher by threaded connec‐

tions and / or special joints ⇒ Heating, air conditioning; Rep.

gr. 87 ; Refrigerancircui(vehicle-specific workshop manual).

♦ Renew the sealing elements (e.g. seals) between the compo‐

nents ⇒ Electronic parts catalogue .

♦ For threaded connections, observe the specified torque set‐

tings. For pressure-ficonnections, use dedicated release

tools ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigeran

circui(vehicle-specific workshop manual).

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1.2.17

High-pressure safety valve

The high pressure safety valve is fitted to the air conditioner com‐

pressor or the receiver.

The valve opens aa pressure of approx. 38 bar (overpressure)

and closes again when the pressure has dropped (to approx. 35

bar).

Noall the refrigeranis losfrom the system.

Note

♦ Depending on the version, a transparenplastic washer -B-

may be attached to the high pressure safety valve -A- which

breaks off as soon as the valve is actuated.

♦ Depending on the version of high pressure safety valve -A-, a

cover -C- may also be pushed onto the high pressure safety

valve -A-. Should the pressure in the refrigerancircuiactually

rise above the opening pressure of the high pressure safety

valve -A- and cause the valve to open, refrigeranwill noes‐

cape in one direction buscatter through the openings -D-

beneath the cover -C- instead.

♦ If a high-pressure safety valve -A- needs to be renewed, the

specified torque for the new valve (depending on the manu‐

facturer and the version of the air conditioner compressor)

musbe observed when installing. Air conditioner compres‐

sors manufactured by “Denso”, “Sanden” and “Valeo” are

equipped with an O-ring seal (currently valid torque settings

are: 10 Nm for “Denso” and “Zexel/Valeo” air conditioner com‐

pressors, and 15 Nm for “Sanden” air conditioner compres‐

sors). Air conditioner compressors manufactured by “Delphi”

are fitted with an oil seal (currently valid torque setting: 15 Nm).

lk

♦ Renewing seals (oil seals or O-rings) ⇒ Electronic parts cata‐

logue .

♦ If a seal (oil seal or O-ring) fitted to the high-pressure safety

valve is noavailable as a replacemenpart, the removed old

parcan be reused (as an exception to the general rule of using

new seals only). The old seal, however, musalways be

checked for damage prior to installation. If any damage or de‐

formation is detected on the old seal, imusbe renewed with

a commercially available new par⇒ Electronic parts cata‐

logue .

♦ After filling the refrigerancircuit, check the installed high-

pressure safety valve for leaks using e.g. an electronic leak

detector.

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1.2.18

Non-return valves

Non-return valves separate the refrigerancircuiinto differen

areas ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerancircui

(vehicle-specific workshop manual).

Note

♦ The non-return valve -3- shown in installed e.g. in the Audi Q7

e-tron ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigeran

circui(vehicle-specific workshop manual).

♦ Non-return valves in the refrigerancircuihave a certain hold‐

ing pressure in the direction of flow (approx. 0.1 bar or

100 mbar). To ensure thathe refrigerancircuican be evac‐

uated completely (residual pressure below 5 mbar), all of the

electrically actuated valves mustherefore be open.

♦ Depending on the version, the direction of flow may be indi‐

cated by a sticker.

lk

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1.2.19

Quick-release coupling connections in

refrigerancircui

Service connections with Schrader valve (needle valve or push

pin)

♦ Only valves and connections resistanto R1234yf refrigeran

and the related refrigeranoils may be used.

♦ Service connections -C- and -F- in an R1234yf refrigerancir‐

cuiare configured in such a way thaservice couplings canno

be connected to service connections designed for an R134a

refrigerancircuit.

♦ Different connections (external diameter) for high pressure

and low pressure side -C- and -F-.

♦ Before removing the valves or valve inserts -B- and -E-, empty

the refrigerancircuit.

♦ Always screw on sealing caps -A- and -D- with seal -G-.

Layouin vehicle ⇒ Heating, air conditioning; Rep. gr. 87 ; Re‐

frigerancircui(vehicle-specific workshop manual).

– Extract refrigeranbefore unscrewing the valves.

♦ Service connection, low pressure side -F-

♦ Service connection, high pressure side -C-

♦ Valve inser(designation: Schrader or needle valve)

♦ Sealing cap for service connection on low pressure side with

seal -A-

♦ Sealing cap for service connection on high pressure side with

seal -D-

lk

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Note

♦ Carefully, and no more than necessary, screw in the hand‐

wheel of the service coupling (after connecting) into the quick

release coupling adapter until the valve in the service connec‐

tion is open (observe pressure gauge; do noover-tighten

valve).

♦ Service connections in an R1234yf refrigerancircuiare con‐

figured in such a way thaservice couplings cannobe con‐

nected to service connections designed for an R134a

refrigerancircuit.

♦ The service connections are brazed into e.g. a refrigeranline

and therefore cannobe replaced individually.

lk

♦ When removing and installing valve core with refrigerancir‐

cuidischarged, use a socke- T10364- or similar.

♦ Exercise caution when tightening the valve inserdue to the

low tightening torque.

♦ There are differenversions of these valves; therefore tight‐

ening torques vary. For a valve inser-C- with a VG5 thread

(5.2 x 0.7 mm, tyre valve) the tightening torque is 0.4 Nm

± 0.1 Nm; for a valve inserwith an M6 x 0.75 mm thread the

tightening torque is 0.9 Nm ± 0.1 Nm, and for a valve inser

with an M8 x 1.0 mm thread the tightening torque is

2.0 Nm ± 0.2 Nm.

♦ These valve caps come in differenversions, which means tha

the specified torques will differ. For a valve cap with an M8 x

1 mm or M10 x 1 mm thread, the specified torque is

0.4 Nm ± 0.1 Nm respectively.

♦ These valves, valve inserts and corresponding sealing caps

come in differenversions. Make sure thathe correctype of

valve inseris used and allocation of the sealing caps is correc

⇒ Electronic parts catalogue .

Dimensions of service connections

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♦ Valve inser-A- (differenversions).

♦ Service connection -B- (differenversions on high pressure

and low pressure side depending on refrigerant)

Dimensions of serv‐ Service connec‐

Service connection

ice connections -B- tion for R134a re‐ for R1234yf refriger‐

frigeran

High-

an

Low-

High-

Low-

pressure pres‐

pressure pressure

side

sure

side

External diameter

-D1-

16.0 mm 13.0 m 17.0 mm 14.0 mm

m

External diameter

14.0 mm 11.0 m 13.0 mm 12.0 mm

m

-D2-

Shoulder -L1-

Shoulder -L2-

4.6 mm 6.15 m 9.0 mm 4.75 mm

m

8.16 mm 9.16 m 12.5 mm 7.2 mm

m

Installation position of 6.1 - 7.1 6.1 - 7.1 8.3 - 9.3 8.3 - 9.3

valve (unactuated)

-C-

mm

Service connections with primary sealing valve (ball valve)

♦ This type of service connection is currently noused in VW/

Audi refrigerancircuits.

♦ Only valves and connections resistanto R1234yf refrigeran

and the related refrigeranoils may be used.

♦ Service connections in an R1234yf refrigerancircuiare con‐

figured in such a way thaservice couplings cannobe con‐

nected to service connections designed for an R134a

refrigerancircuit.

♦ Different connections (external diameter) for high-pressure

and low-pressure sides.

♦ Discharge refrigerancircuibefore removing valve or valve

inserts.

♦ Always screw on sealing caps with seal.

Layouin vehicle ⇒ Heating, air conditioning; Rep. gr. 87 ; Re‐

frigerancircui(vehicle-specific workshop manual).

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Connection with high pressure valve

1 - Boss with internal thread (brazed on)

2 - Seal (version and designation: black or coloured ⇒ Elec‐

tronic parts catalogue )

3 - Valve with external thread and groove for seal (designation:

ball valve)

4 - Seal for sealing cap

5 - Sealing cap

Note

♦ Carefully, and no more than necessary, screw in the hand‐

wheel of the service coupling (after connecting) into the quick

release coupling adapter until the valve in the service connec‐

tion is open (observe pressure gauge; do noover-tighten

valve).

♦ When removing and installing the valve -3- with purged refrig‐

erancircuit, use e.g. an adapter from sockese- T10364- .

♦ These valves come in differenversions (with internal or ex‐

ternal thread) and the specified torques can therefore differ.

For the valves -3- currently in use (external thread M12 x 1.5

mm) the tightening torque is 9 Nm ± 1 Nm.

♦ These valves and corresponding sealing caps come in differ‐

enversions. Make sure thathe correctype of valve is used

and allocation of the sealing caps is correc⇒ Electronic parts

catalogue .

Connection with low pressure valve

lk

1 - Boss with external thread and groove for O-ring (brazed in)

2 - Seal (version and designation: black or coloured ⇒ Elec‐

tronic parts catalogue )

3 - Valve with internal thread

4 - Seal for sealing cap

5 - Sealing cap

Note

♦ Carefully, and no more than necessary, screw in the hand‐

wheel of the service coupling into the quick release coupling

adapter until the valve in the service connection is open (ob‐

serve pressure gauge; do noover-tighten valve).

♦ When removing and installing the valve -3- with purged refrig‐

erancircuit, use e.g. an adapter from sockese- T10364- .

♦ These valves come in differenversions (with internal or ex‐

ternal thread) and the specified torques can therefore differ.

For the valves -3- currently in use (internal thread

M10 x 1.25 mm) the tightening torque is 9 Nm ± 1 Nm.

♦ These valves and corresponding sealing caps come in differ‐

enversions. Make sure thathe correctype of valve is used

and allocation of the sealing caps is correc⇒ Electronic parts

catalogue .

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1.2.20

Connections with valve for switches in

refrigerancircui

Note

Refer to vehicle-specific refrigerancircuifor switching pres‐

sures, removing and installing switches and location/design of

switches ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigeran

circui(vehicle-specific workshop manual).

•

The switches on the high pressure and low pressure sides

have differenthreads.

Only valves and seals resistanto R1234yf refrigeranand the

related refrigeranoils may be used ⇒ Electronic parts cata‐

logue .

A - Connection (brazed)

B - Seal

C - Valve (with seal)

lk

Note

♦ To remove and install the valve -C- with the refrigerancircui

empty, use e.g. an adapter from sockese- T10364- (speci‐

fied torque ⇒ page 55 ).

♦ There are differenversions of these valves; therefore tight‐

ening torques vary. For a valve inser-C- with a VG5 thread

(5.2 x 0.7 mm, tyre valve) the tightening torque is 0.4 Nm

± 0.1 Nm; for a valve inserwith an M6 x 0.75 mm thread the

tightening torque is 0.9 Nm ± 0.1 Nm, and for a valve inser

with an M8 x 1.0 mm thread the tightening torque is

2.0 Nm ± 0.2 Nm.

1.2.21

Pressure senders and switches in refrig‐

erancircui

Note

♦ Pressure senders and switches come in differenversions,

with differenfunctions and differendesignations ⇒ Heating,

air conditioning; Rep. gr. 87 ; Refrigerancircui(vehicle-spe‐

cific workshop manual).

♦ Switching pressures, removing and installing switches and

switch layouand type ⇒ Heating, air conditioning; Rep. gr.

87 ; Refrigerancircui(vehicle-specific workshop manual).

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♦ The high pressure sender shown is installed e.g. in the Golf 7

and Audi A3 ⇒ Heating, air conditioning; Rep. gr. 87 ; Re‐

frigerancircui(vehicle-specific workshop manual).

♦ One version of pressure sender generates a square-wave sig‐

nal when voltage is applied. This signal changes with the

pressure in the system. The other version of pressure sender

exchanges information with the corresponding control univia

data bus (e.g. via the “LIN bus”) when voltage is applied ⇒ Cur‐

renflow diagrams, Electrical faulfinding and Fitting locations

and ⇒ Vehicle diagnostic tester in “Guided FaulFinding”

mode - air conditioning system. Therefore, pay attention to the

correcversion of pressure sender.

♦ The pressure senders come in differenversions. Depending

on the version, they can currently only be distinguished exter‐

nally by the parnumber, which is why attention should be paid

during renewal to their correcallocation (parnumber ⇒ Elec‐

tronic parts catalogue ). Reason: These senders emidifferen

lk

signals, and the relevancontrol units can only evaluate the

signal to which they have been matched ⇒ Vehicle diagnostic

tester in “Guided FaulFinding” mode - air conditioning system

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

cui(vehicle-specific workshop manual).

♦ One version of pressure sender only transmits the measured

value for the pressure in the refrigerancircuito the connected

control unit. The other version transmits the measured value

for the pressure in the refrigerancircuiand the measured

temperature to the connected control unit, which is why atten‐

tion should be paid to the correcversion ⇒ Electronic parts

catalogue .

♦ With this signal, the downstream control units calculate the

pressure in the refrigerancircuiand actuate the radiator fans

and engine, the air conditioning system magnetic clutch - N25-

accordingly or manipulate actuation of the air conditioner com‐

pressor regulating valve - N280- ⇒ Vehicle diagnostic tester in

“Guided FaulFinding” mode - air conditioning system and ⇒

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

hicle-specific workshop manual).

1.2.22

Refrigeranpressure and temperature

sender

CAUTION

Risk of freezing injury caused by escaping pressurised refrig‐

erant.

There is a risk of injury to the skin and parts of the body due to

freezing.

– Wear protective gloves.

– Wear protective goggles.

– Extract refrigeranand open the refrigerancircuiimmedi‐

ately afterwards.

– If more than 10 minutes have passed since the refrigeran

was extracted, repeathe extraction process before opening

the refrigerancircuit. Pressure could build up in the refrig‐

erancircuifrom continued evaporation.

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Senders for connection to a refrigerancircuiwith valve

Note

♦ Refer to vehicle-specific refrigerancircuifor switching pres‐

sures, removing and installing switches and location/design of

switches ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigeran

circui(vehicle-specific workshop manual).

♦ These senders come in differenversions, with differenfunc‐

tions and differendesignations. The refrigeranpressure and

temperature sender - G395- shown as follows is installed e.g.

in the Golf GTE, Audi A4, Audi Q5 and Audi Q5 Hybrid ⇒

Heating, air conditioning; Rep. gr. 87 ; Refrigerancircuit;

System overview - refrigerancircui.

♦ Before loosening the threaded connection of the sender,

check which version of sender iis ⇒ Heating, air conditioning;

Rep. gr. 87 ; Refrigerancircuit; System overview - refrigeran

circui.

♦ For senders designed for connection to a refrigerancircui

withouvalve. The refrigeranmusbe extracted before the

threaded connection is loosened. If the sender is noremoved

within 10 minutes after the system has been evacuated, pres‐

sure may develop in the refrigerancircuidue to re-evapora‐

tion. Extracrefrigeranagain.

♦ Differendesignations depending on the function and vehicle

lk

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerancircuit;

System overview - refrigerancircui.

♦ The sender for refrigeranpressure and refrigerantempera‐

ture is installed e.g. in place of the high pressure sender or

pressure sender for refrigerancircui⇒ Heating, air condi‐

tioning; Rep. gr. 87 ; Refrigerancircui(vehicle-specific work‐

shop manual)

♦ The sender for refrigeranpressure and refrigerantempera‐

ture, the pressure sender for refrigerancircuiand high pres‐

sure sender come in differenversions. Depending on the

version, they can currently only be distinguished externally by

the parnumber, which is why attention should be paid during

renewal to their correcallocation (parnumber ⇒ Electronic

parts catalogue ). Reason: These senders emidifferensig‐

nals, and the relevancontrol units can only evaluate the signal

to which they have been matched ⇒ Vehicle diagnostic tester

in “Guided FaulFinding” mode - air conditioning system and

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerancircui

(vehicle-specific workshop manual).

♦ The sender for refrigeranpressure and refrigerantempera‐

ture (and the pressure sender for refrigerancircuit) exchange

information with the respective control univia the data bus

(e.g. “LIN bus”) when voltage is applied. The respective control

units use this information to calculate the pressure and tem‐

perature in the refrigerancircuit. Any faults detected in this

way are passed on to the control uni⇒ Vehicle diagnostic

tester in “Guided FaulFinding” mode.

♦ The sender for refrigeranpressure and refrigerantempera‐

ture transmits the measured valve for the pressure in the

refrigerancircuiand the measured temperature to the con‐

nected control unit. The pressure sender for refrigerancircui

only transmits the measured value for the pressure in the re‐

frigerancircuito the connected control unit. Even though on

mosvehicles only the pressure signal is evaluated, no other

pressure sender may be installed in a vehicle for which provi‐

sion is made for a refrigeranpressure and refrigerantem‐

perature sender ⇒ Electronic parts catalogue .

1. Refrigerancircui

61

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

♦ The temperature measured by this refrigeranpressure and

lk

temperature sender deviates from the actual temperature of

the refrigeranin the refrigerancircuiowing to the design of

the sender and the fitting location. Iis therefore noevaluated

apresenby all control units and is used to regulate the air

conditioning system ⇒ Heating, air conditioning; Rep. gr. 87 ;

Refrigerancircuit; System overview - refrigerancircui(vehi‐

cle-specific workshop manual).

♦ With this information, the respective control units calculate the

pressure in the refrigerancircuiand actuate the downstream

control units (radiator fan control unit, engine control unietc.)

via data bus. These control units subsequently actuate e.g. the

air conditioning system magnetic clutch - N25- , the radiator

fan and the engine ⇒ Vehicle diagnostic tester in “Guided Faul

Finding” mode - air conditioning system and ⇒ Heating, air

conditioning; Rep. gr. 87 ; Refrigerancircui(vehicle-specific

workshop manual).

Senders for connection to a refrigerancircuiwithouvalve

Note

♦ These senders come in differenversions, with differenfunc‐

tions and differendesignations. The sender for refrigeran

pressure and refrigerantemperature shown as follows is in‐

stalled e.g. in the Audi Q7 e-tron ⇒ Heating, air conditioning;

Rep. gr. 87 ; Refrigerancircuit; System overview - refrigeran

circui.

♦ Differendesignations depending on the function and vehicle

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerancircuit;

System overview - refrigerancircui.

Possible designations for these senders

♦ Refrigerant pressure and temperature sender - G395- (e.g. in

e-Golf, Audi Q7 e-tron)

♦ Refrigerant pressure and temperature sender 2 - G826- (e.g.

in Audi Q7 e-tron)

♦ Refrigerant pressure and temperature sender 3 - G827- (e.g.

in Audi Q7 e-tron)

These senders -A- come in differenversions that, depending on

the version, can currently only be distinguished externally by the

parnumber or, if the parnumber is the same, by the designation

label -B-, which is why when renewing them iis importanto en‐

sure the correcallocation. Parnumber and designation ⇒

Electronic parts catalogue and ⇒ Heating, air conditioning; Rep.

gr. 87 ; Refrigerancircuit; System overview - Refrigerancircui.

When a voltage is applied, these senders exchange information

with the respective control univia the data bus (e.g. via “LIN

bus”). The respective control units use this information to calcu‐

late the pressure and temperature in the refrigerancircuit. Any

faults detected in this way are passed on to the control uni⇒ Ve‐

hicle diagnostic tester in “Guided FaulFinding” mode.

With this information, the respective control unicalculates the

pressure in the refrigerancircuiand actuates the downstream

control units or components (radiator fan control unit, pumps,

valves etc.) via data bus according to the specifications ⇒ Vehicle

diagnostic tester in “Guided FaulFinding” mode and ⇒ Heating,

air conditioning; Rep. gr. 87 ; Refrigerancircuit; System overview

- refrigerancircui(vehicle-specific workshop manual).

62

Rep. gr.87 - Air conditioning system

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

1.2.23

Air conditioner compressor regulating

valve - N280-

Note

Refer to vehicle-specific refrigerancircuifor switching pres‐

sures, removing and installing switches and location/design of

switches ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigeran

circuit; System overview - refrigerancircui.

♦ The regulating valve is fitted to the air conditioner compressor.

Iis actuated, for example, by the air conditioning system con‐

trol uni- J301- , the operating and display unifor fronair

conditioning system - E87- or the Climatronic control uni-

J255- (potentially also via data bus and an additional control

unidepending on the vehicle) ⇒ Vehicle diagnostic tester in

“Guided FaulFinding” mode - air conditioning system and ⇒

lk

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

hicle-specific workshop manual).

♦ The regulating valve influences the pressure on the low pres‐

sure side and thus the temperature athe evaporator.

Note

The air conditioner compressor regulating valve - N280- is an in‐

tegral parof the air conditioner compressor and cannobe re‐

newed individually on all air conditioner compressors ⇒

Electronic parts catalogue .

1.2.24

Refrigerantemperature sender

Note

♦ A refrigerantemperature sender (a temperature sender tha

does noevaluate the pressures) is currently noused by

Volkswagen/Audi.

♦ Switching pressures, removing and installing switches and

switch layouand design ⇒ Vehicle diagnostic tester in “Gui‐

ded FaulFinding” mode - air conditioning system and ⇒

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

hicle-specific workshop manual).

1. Refrigerancircui

63

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

♦ The refrigerantemperature sender (with temperature-de‐

pendenresistor) is installed e.g. in the high pressure line in

the vicinity of the air conditioner compressor.

♦ There is a direccorrelation between temperature and pres‐

sure in the refrigerancircuit: if there is too little refrigeranin

the refrigerancircuit, the temperature in the refrigerancircui

rises during operation of the air conditioning system on the

high pressure side greater than permitted for this pressure.

Note

The respective control unit, e.g. the operating and display unifor

lk

fronair conditioning system - E87- or the Climatronic control uni

- J255- evaluates the pressure and the temperature in the refrig‐

erancircuiand switches off the air conditioner compressor if the

temperature increases above the value stored for this pressure

⇒ Vehicle diagnostic tester in “Guided FaulFinding” mode - air

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

87 ; Refrigerancircui(vehicle-specific workshop manual).

1.3

Possible complaints

⇒ “1.3.1 Prerequisites for investigating a complaint”, page 64

⇒ “1.3.2 Possible complaints”, page 64

⇒ “1.3.3 Odours from heater and air conditioner unit”, page 66

1.3.1

Prerequisites for investigating a com‐

plain

•

No faulwas evidenduring faulfinding in the electrical sys‐

tem, vacuum system and air ducts/channels ⇒ Vehicle diag‐

nostic tester in “Guided FaulFinding” mode - air conditioning

system (and battery control), ⇒ Currenflow diagrams, Elec‐

trical faulfinding and Fitting locations and ⇒ Heating, air

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

ing outpu.

•

Self-diagnosis in “Guided FaulFinding” mode - air condition‐

ing system (e.g. using ⇒ Vehicle diagnostic tester in “Guided

FaulFinding” mode - air conditioning system) provides no

evidence of a complaint.

No shut-off condition for the air conditioner compressor is dis‐

played in the measured values of the control uniof the air

conditioning system ⇒ Vehicle diagnostic tester in “Guided

FaulFinding” mode - air conditioning system.

1.3.2

Possible complaints

Note

♦ For all complaints marked with *

⇒ “2.14 Checking pressures”, page 170 .

♦ If on vehicles with 2 evaporators a problem is encountered in

jusone evaporator, check the pressures in the refrigerancir‐

cuias well ⇒ “2.14 Checking pressures”, page 170 .

♦ The cooling has failed completely.*

♦ Insufficient cooling outpuaall vehicle speeds and engine

speeds.*

♦ No or insufficiencooling after driving a few miles. *

64

Rep. gr.87 - Air conditioning system

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Air conditioning system Refrigerant circuit -> 1.2 General description - components of refrigerant circuit for Your Volkswagen Sharan VAN Second Generation (2010-2023)

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