Audi A3 1997 User manual

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
Audi A3 1997 ➤
Heating, Air Conditioner
Edition 06.2000
Service
Service Department. Technical Information

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
List of Workshop Manual Repair GroupsList of Workshop Manual
Repair GroupsList of Workshop Manual Repair Groups
Audi A3 1997 ➤
Heating, Air Conditioner
Repair Group
01 - Self-diagnosis, Electrical check
80 - Heating
87 - Air conditioning
Technical information should always be available to the foremen and mechanics, because their careful
and constant adherence to the instructions is essential to ensure vehicle road-worthiness and safety. In
addition, the normal basic safety precautions for working on motor vehicles must, as a matter of course,
be observed.
Service
All rights reserved.
No reproduction without prior agreement from publisher.
Copyright © 2010 Audi AG, Ingolstadt A0050006320

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
Contents
01 - Self-diagnosis, Electrical check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1 Air conditioner self-diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.1 Air conditioner self-diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2 Assignment of the operating and display unit -E87 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.3 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
1.4 Technical self-diagnosis data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.5 Self-diagnosis test prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.6 Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2 Connecting vehicle diagnosis, measurement and information system VAS 5051 or fault
reader V.A.G 1551 and selecting function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2.1 Connecting vehicle diagnosis, measurement and information system VAS 5051 or fault
reader V.A.G 1551 and selecting function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
3 Interrogating fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.1 Interrogating fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
4 Fault table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
4.1 Fault table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
5 Final control diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
5.1 Final control diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
6 Basic setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
6.1 Basic setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
7 Erasing fault memory, ending output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
7.1 Erasing fault memory, ending output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
8 Encoding operating and display unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
8.1 Encoding operating and display unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
8.2 Coding of operating and display unit with two displays . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
8.3 Coding of operating and display unit with one display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
9 Reading measured value block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
9.1 Reading measured value block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
9.2 Display groups 001 to 006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
9.3 Display groups 007 to 012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
10 AC electrical check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
10.1 AC electrical check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
10.2 Electrical check on operating and display unit -E87 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
10.3 Test in vehicles with an operating and display unit with two displays . . . . . . . . . . . . . . . . . .48
10.4 Checking in vehicles with an operating and display unit with one display . . . . . . . . . . . . . .60
11 Perform electrical check at radiator fan control unit -J293 . . . . . . . . . . . . . . . . . . . . . . . . . .70
11.1 Perform electrical check at radiator fan control unit -J293 . . . . . . . . . . . . . . . . . . . . . . . . . .70
11.2 Electrical check at control unit -J293 (version for pressure switch -F129) . . . . . . . . . . . . . .71
11.3 Electrical check at control unit -J293 (version for High-pressure sensor -G65) . . . . . . . . . .76
11.4 Check signal from high-pressure sensor -G65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
12 Electrical check of rear window heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
12.1 Electrical check of rear window heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
80 - Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
1 Servicing heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
1.1 Servicing heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
1.2 Dash panel vents and air ducts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
1.3 Removing and installing centre dash-panel vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
1.4 Making an auxiliary tool for dismantling the dash panel vents . . . . . . . . . . . . . . . . . . . . . . . .92
1.5 Removing and installing "left" and "right" dash panel vent . . . . . . . . . . . . . . . . . . . . . . . . . .92
1.6 Removing and installing windscreen defroster vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
1.7 Checking vent frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
Contents i

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
1.8 Removing and installing air duct to defroster vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94
1.9 Heating, heater control and air ducts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95
1.10 Removing and installing heater control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100
1.11 Detaching and fitting Bowden cables from/on heater control . . . . . . . . . . . . . . . . . . . . . . . .104
1.12 Connection diagram for Bowden cables to the heater control . . . . . . . . . . . . . . . . . . . . . . . .104
1.13 Connection diagram for Bowden cables on the heater control . . . . . . . . . . . . . . . . . . . . . . . .105
1.14 Removing, installing and adjusting Bowden cables from/on the heater control . . . . . . . . . .105
1.15 Replacing the bulb for heater control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
1.16 Removing and installing fresh air blower -V2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108
1.17 Removing and installing series resistor -N24 for fresh air blower . . . . . . . . . . . . . . . . . . . .108
1.18 Removing and installing positioning motor for fresh/recirculated air flap -V154 . . . . . . . . . .109
1.19 Checking the function of the positioning motor for fresh/recirculated air flap -V154 and switch
-E159 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110
1.20 Removing and installing footwell vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112
1.21 Removing and installing dust and pollen filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
1.22 Connection diagram for vacuum hoses for actuating the refrigerant shut-off valve . . . . . . . .114
1.23 Notes on heater in vehicles with map-controlled heating . . . . . . . . . . . . . . . . . . . . . . . . . . . .115
2 Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
2.1 Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
2.2 Special tools, testers, measuring instruments and auxiliary items required . . . . . . . . . . . . . .116
3 Removing and installing heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
3.1 Removing and installing heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
3.2 Removing and installing heating system heat exchanger . . . . . . . . . . . . . . . . . . . . . . . . . .122
4 Servicing electrical additional heater - Vehicles with TDI engine . . . . . . . . . . . . . . . . . . . . . .123
4.1 Servicing electrical additional heater - Vehicles with TDI engine . . . . . . . . . . . . . . . . . . . . . .123
4.2 Checking function of electrical additional heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
87 - Air conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125
1 Safety precautions when working on cars with air conditioners and when handling refrigerant
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125
1.1 Safety precautions when working on cars with air conditioners and when handling refrigerant
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125
2 Notes on general repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
2.1 Notes on general repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
2.2 Notes on air conditioner in vehicles with map-controlled heating . . . . . . . . . . . . . . . . . . . . . .127
3 Repairing refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
3.1 Repairing refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
3.2 Air conditioner pressure switch -F129 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
3.3 Remove and install High-pressure sensor -G65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137
3.4 O-ring seals for refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137
3.5 Detach and re-attach compressor from/to bracket (4 cyl. petrol engine) . . . . . . . . . . . . . . . .138
3.6 Detach and re-attach compressor from/to bracket (4 cyl. petrol engine) . . . . . . . . . . . . . . . .138
4 Repairing the air conditioner magnetic clutch -N25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
4.1 Repairing the air conditioner magnetic clutch -N25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
4.2 Sanden compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
4.3 "Zexel" compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .146
5 Components for the control and regulation of the air conditioner (in the engine compartment)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150
5.1 Components for the control and regulation of the air conditioner (in the engine compartment)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150
5.2 Removing and installing radiator fan control unit -J293 . . . . . . . . . . . . . . . . . . . . . . . . . . . .161
5.3 Checking condensation drain, removing and installing valve . . . . . . . . . . . . . . . . . . . . . . . .161
5.4 Removing and installing heat insulation for the expansion valve . . . . . . . . . . . . . . . . . . . . . .162
5.5 Connection diagram for vacuum hoses for actuating the refrigerant shut-off valve . . . . . . . .163
6 Components for air conditioner control and regulation (in the passenger compartment) . . . .165
6.1 Components for air conditioner control and regulation (in the passenger compartment) . . . .165
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
ii Contents

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
6.2 Removing and installing operating and display unit -E87 . . . . . . . . . . . . . . . . . . . . . . . . . . . .174
6.3 Removing and installing blower control unit -J126 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .178
6.4 Removing and installing footwell vent temperature sender -G192 . . . . . . . . . . . . . . . . . . . .178
6.5 Removing and installing centre vent temperature sensor -G191 . . . . . . . . . . . . . . . . . . . . . .179
6.6 Removing and installing fresh air blower -V2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179
6.7 Removing and installing sunlight penetration photosensor -G107 . . . . . . . . . . . . . . . . . . . .180
6.8 Removing and installing footwell vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .181
6.9 Removing and installing footwell/defroster flap positioning motor -V85 . . . . . . . . . . . . . . . .181
6.10 Removing and installing temperature flap positioning motor - Remove and install -V68 . . . .182
6.11 Removing and installing central flap positioning motor -V70 . . . . . . . . . . . . . . . . . . . . . . . .182
6.12 Removing and installing dash panel temperature sensor -G56 . . . . . . . . . . . . . . . . . . . . . .183
6.13 Removing and installing dash panel temperature sensor blower -V42 . . . . . . . . . . . . . . . .184
6.14 Removing and installing fresh air intake temperature sensor -G89 . . . . . . . . . . . . . . . . . . . .185
6.15 Removing and installing air flow flap positioning motor -V71 . . . . . . . . . . . . . . . . . . . . . . . .185
7 Checking air conditioner refrigeration capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186
7.1 Checking air conditioner refrigeration capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186
8 Servicing electrical additional heater - Vehicles with TDI engine 06.94 ä . . . . . . . . . . . . . .190
8.1 Servicing electrical additional heater - Vehicles with TDI engine 06.94 ä . . . . . . . . . . . . . .190
8.2 Checking function of electrical additional heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .190
9 Repairing refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .191
9.1 Repairing refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .191
9.2 Removing and installing fluid reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201
9.3 Removing and installing condenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201
9.4 Detach and re-attach refrigerant lines from/to expansion valve . . . . . . . . . . . . . . . . . . . . . .203
9.5 Removing and installing expansion valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .203
9.6 Detach and re-attach refrigerant lines from/to compressor . . . . . . . . . . . . . . . . . . . . . . . . . .204
9.7 Removing and installing compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .204
9.8 Filling quantities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205
10 Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205
10.1 Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205
10.2 Special tools, testers, measuring instruments and auxiliary items required . . . . . . . . . . . . . .205
11 Removing and installing air conditioner (complete) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .206
11.1 Removing and installing air conditioner (complete) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .206
11.2 Removing and installing the air conditioner heat exchanger . . . . . . . . . . . . . . . . . . . . . . . .212
12 Dismantle and assemble air conditioner (version 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .213
12.1 Dismantle and assemble air conditioner (version 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .213
12.2 Disassembling and assembling evaporator housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .218
13 Dismantle and assemble air conditioner (version 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .223
13.1 Dismantle and assemble air conditioner (version 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .223
13.2 Removing and installing air conditioner attachment parts . . . . . . . . . . . . . . . . . . . . . . . . . .224
13.3 Removing and installing air conditioner electrical components . . . . . . . . . . . . . . . . . . . . . .227
13.4 Dismantling and assembling air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .231
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
Contents iii

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
iv Contents

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
01 - Self-diagnosis, Electrical check
1 - Air conditioner self-diagnosis
1.1 - Air conditioner self-diagnosis
1.2 - Assignment of the operating and display unit -E87
Part number Special features
8L0 820 043 A ... C Model with two displays:
▪ For all vehicles of model year 97
Illumination of the -E87 is via ter‐
minal 58 and 58d
8L0 820 043 D or
EModel with two displays. Illumination of the -E87 is also via
terminal 58s.
▪ For vehicles of model years
1998 and 1999.
Not for vehicles with map-control‐
led cooling
8L0 820 043 M
or N Model with two displays. Assignment of ignition key is rec‐
ognised.
▪ For vehicles with map zone
cooling (model years 1999 and
2000 only).
▪ For all vehicles of model year
2000)
Part number Special features
8L0 820 043 H, J,
K or L
and
from O
onwards
Model with one display.
▪ For all vehicles from Model Year
2001.
Notes:
◆ Note the precise assignment when replacing an operating and display unit -E87:
=> Parts List
◆ Different designs for the operating and display unit -E876 as of model year 2001 in vehicles with and without
a radio navigation system (or radio with large display zone) with and without switches for heated seats (e.g.
Index "H", "J", "K" or "L").
=> Parts List
◆ Air conditioner control remains in operation during self-diagnosis.
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
1.1 - Air conditioner self-diagnosis 1

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
1.3 - Function
Air conditioner control and display unit -E87 (control unit) receives information from electrical and electronic
components (signal senders) and then processes this information according to the programmed specified val‐
ues.
The output signals of the control unit then regulate the electrical components (control elements).
To enable the cause of the problem to be established quickly in the event of a component failure or open circuit
in wiring, operating and display unit -E87 is equipped with a fault memory which can be read with fault reader
V.A.G 1551, vehicle diagnosis system VAS 5051 or vehicle system tester V.A.G 1552.
If faults occur in the monitored sensors and components, these are stored in the fault memory together with an
indication of type of fault.
Always commence fault finding by starting self-diagnosis and interrogating the stored information with
fault reader V.A.G 1551
vehicle system tester V.A.G 1552,
or
vehicle diagnostic, measuring and information system VAS 5051.
The fault information which is displayed indicates specific repair measures via a fault table.
Notes on fault remedy:
◆ Data output is only possible with the ignition switched on or with the engine running and an engine speed
of less than 3000 rpm. At higher engine speeds, data output is restricted or terminated (for example, final
control diagnosis can only be implemented up to an engine speed of 3000 rpm; if this speed is exceeded,
self-diagnosis is terminated).
◆ If a fault situation exists for longer than a specific period, the fault is stored as a static fault. If the fault is no
longer present after a specified period, it becomes a sporadic fault. This process is constantly repeated.
Sporadic faults are also identified as such (the letters /SP appear on the display).
◆ If a sporadic fault ceases to occur for a specific period, it is automatically erased.
The possibilities offered by self-diagnosis can only be utilised by employing fault reader V.A.G 1551 (mode 1,
"Rapid data transfer"), V.A.G 1552, or VAS 5051.
Self-diagnosis is not restricted to storage, interrogation, erasing and final control diagnosis. It also has basic
setting, control unit identification and encoding functions.
Mode -2- (flash code output) is not envisaged for electronic climate/heating control. Modes -3- (self-test) and
-4- (dealership identification) only apply to fault reader V.A.G 1551 and vehicle system tester V.A.G 1552 and
are described in the appropriate manuals.
Note:
The following describes self-diagnosis using the fault reader V.A.G 1551 only.
Self-diagnosis can also be performed in the same manner with VAS 5051 or V.A.G 1552. In order to be able
to provide proof of faults in the event of subsequent queries, it is advisable to print out any faults found after
interrogating the fault memory.
If the fault memory has been read out using V.A.G 1552, before erasing the fault memory, connect V.A.G 1551
or VAS 5051 and print out the faults found (V.A.G 1552 does not have a printer).
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
2 01 - Self-diagnosis, Electrical check

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
1.4 - Technical self-diagnosis data
▪ Memory Non-volatile memory
▪ Data output Rapid data transfer "Mode 1"
▪ self-diagnosis Electronic climate/heating control"Address word 08"
- Check control unit version Function 01
- Interrogating fault memory Function 02
- Performing final control diagnosis Function 03
- Performing basic setting Function 04
- Erasing fault memory Function 05
- End of output Function 06
- Encoding control unit Function 07
- Reading measured value block Function 08
Notes:
◆ Fitting locations of components => Page 165 .
◆ If a newly installed operating and display unit has not been encoded, or if an impermissible code has been
entered into operating and display unit -E87 the coding "04042" (Audi A4 - 4 cyl -USA) is stored or the
previous coding remains. The model with one display the fault "coding not accepted" is displayed with fault
during coding.
◆ If the display of a newly installed operating and display unit flashes (for approx. 2 minutes) after the ignition
is switched on, encode the operating and display unit and perform basic setting.
◆ Air conditioner control remains operational and is not terminated on entering into self-diagnosis mode (com‐
pressor, positioning motors, radiator fan etc. can be actuated).
◆ Air conditioner control is not terminated on entering into self-diagnosis mode. However, it is deactivated if
the following functions are selected:
- Perform final control diagnosis
- Perform basic setting.
When the other functions are selected, the control function remains fully operative.
◆ Operating and display unit -E87 is no longer connected to terminal 30 of the vehicle electrical system. The
last valid setting (on operating and display unit -E87) is stored in -E87 on switching off the ignition and is re-
activated when the ignition is switched on.
◆ The elapsed time interval after the ignition is switched off is calculated by operating and display unit -E87
when the ignition is switched on (time signal is supplied by dash panel insert). If more than 4 hours have
elapsed since the ignition was switched off, the current measured values of the ambient temperature sensor
are used as temporary ambient and engine temperature for purposes of system control. If the "standing
time" was less than 4 hours, the current values are calculated by the operating and display unit -E 887 (since
heat radiation from the engine and radiator leads to incorrect measurements, the current values measured
by the temperature sensors are suppressed for a specific period).
◆ For purposes of air conditioner control and for the ambient temperature display, the lower of the two tem‐
perature values measured by the ambient temperature sensors is used.
◆ The assignment of the terminal at the operating and display unit -E87 has been changed for model year
1998 (vehicles with an operating and display unit -E87 as of index "D"), (inputs for illumination, terminal 58,
terminal 58s).
◆ Vehicles as of model year 2001 a revised operating and display unit -E87 has been installed. Plug A is no
longer present in this type.
1.5 - Self-diagnosis test prerequisites
◆ All fuses OK in line with current flow diagram.
◆ Battery voltage OK
◆ The ignition must be switched on or the engine must be running.
(Engine speed below 3000 rpm)
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
1.4 - Technical self-diagnosis data 3

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
1.6 - Safety precautions
Note the following points if testers and measuring instruments have to be used during a road test:
Important:
◆ Always attach testers and measuring instruments to the back seat and have a second person operate them
from there.
◆ If test equipment were operated from the front passenger seat, the person sitting there could be injured if
the front passenger airbag were triggered in the event of an accident.
2 - Connecting vehicle diagnosis, measurement and information system VAS
5051 or fault reader V.A.G 1551 and selecting function
2.1 - Connecting vehicle diagnosis, measurement and information system VAS 5051 or fault
reader V.A.G 1551 and selecting function
- Switch ignition off.
- -> Remove cover for diagnosis plug (only in vehicles up to model year 2000).
- Connect fault reader V.A.G 1551 using cable V.A.G 1551/3.
Notes:
◆ The illustration shows the arrangement of the diagnosis plug in vehicles up to model year 2000. In vehicles
as of model year 2001 the diagnosis plug is located near the "right-hand A-pillar" in the cover underneath
the dash panel.
◆ Alternatively the vehicle diagnosis, measuring and information system VAS 5051 can be connected with the
diagnosis wire VAS 5051/1 or the vehicle system tester V.A.G 1552 with diagnosis wire V.A.G 1551/3.
◆ If testers and measuring equipment have to be used during a test drive, observe safety precautions => Page
4
◆ The following describes self-diagnosis using the fault reader V.A.G 1551 only.
◆ When using vehicle diagnosis, measurement and information system VAS 5051, or the vehicle system tester
V.A.G 1552, follow the procedures described in the appropriate operating instructions.
-> Display:
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
4 01 - Self-diagnosis, Electrical check

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
font=symbol charset=fontspecific code=042 is displayed alternately.
V.A.G self-diagnosis HELP
1 - Rapid data transfer*
2 - Flash code output*
Notes:
◆ If nothing is displayed on the fault reader V.A.G 1551, check wiring for diagnostic connector according to
current flow diagram.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
◆ Depending on the program, additional operating instructions can be printed out by pressing the HELP key
on V.A.G 1551.
◆ Use the ⇒key to continue through the program.
◆ The PRINT key switches on the printer (lamp in the key lights up).
◆ The fault memory cannot be erased until it has been interrogated.
- Switch on ignition/start engine.
- Switch on compressor (press "Auto" button of operating and display unit -E87).
- Press key -1- to select "Rapid data transfer" mode.
Note:
To check the vehicle speed signal (in the "Reading measured value block" function), move vehicle a few metres
at walking pace before entering into self-diagnosis mode.
-> Display:
Rapid data transfer HELP
Enter address word XX
- Press keys -0- and -8- (08 enters address word for testing the vehicle's "electronic climate/heating control").
-> Indicated on display:
Rapid data transfer Q
08 - Electronic climate/heating control
- Press Q to confirm entry.
-> Display following input of the address word 08:
Rapid data transfer
Tester transmits address word 08
-> After a short time, the control unit identification, the code and the workshop code for the V.A.G 1551 are
displayed:
8L0 820 043 X A3 Fully aut. air
cond. DXX
Code XXXXX WSC ZZZZZ
Control unit identification (example)
- 8L0 820 043 X Part-No.; assignment
=> Parts List
- A3 Full air conditioner Audi A3 control unit for fully
automatic air conditioner
- DXX Control unit data status (soft‐
ware type)
- Code XXXXX: Different codings => Page
27
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
2.1 - Connecting vehicle diagnosis, measurement and information system VAS 5051 or
fault reader V.A.G 1551 and selecting function 5

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
- WSC XXXXX: Workshop Code for the V.A.G
1551 which was used to per‐
form the last encoding
Notes:
◆ Depending on the coding, the displayed vehicle type is A3 or A4 (up to index "E"). A4 is always displayed
for newly installed operating and display units that have not yet been encoded =>Page 3 .
◆ For vehicles with map-controlled cooling (for 1.6 l engine to be gradually introduced as from model year
1999):
- The codes for the operating and display unit -E87 are different to those for vehicles without map-controlled
cooling.
- A centre vent temperature sender -G191 is also installed (in air duct for "centre" dash panel vent).
- The -E87 must be adjusted to the other set-up for the engine cooling via a different code (the refrigerant
temperature is controlled by the engine control unit according to the engine load and is higher when the
engine is running at part throttle in comparison to full throttle).
◆
8L0 820 043 H A3 Fully aut. air
cond. DXX
Code XXXXX WSC ZZZZZ
-> Only an operating and display unit -E87 with part number 8L0 820 043 as of index "H" can be installed
in vehicles with map-controlled cooling, as the map-controlled cooling coding is only recognised as of this
index. As indices "H", "J", "K" and "L" are already allocated to a modified version of -E87 (use in series
production as of model years 2001), operating and display units with part number 8L0 820 043 and indexes
"M" (or "N" for Japan) will be installed until production has been reorganised.
◆ The codes for the operating and control unit -E87 vary from the versions with part number 8L0 820 043 up
to index "E", indices "M" and "N", indices "H", "J", "K" and "L" and as of index "O".
◆ As of model year 2000, the assignment of the ignition key is conveyed by the dash panel insert (data tele‐
gram) together with the refrigerant temperature (when ignition is switched on). This information can only be
processed by operating and display unit -E87 with part number 8L0 820 043 as of index "H". As the indices
"H", "J", "K" and "L" are already allocated to a modified version of -E87 (use in series production for model
years 2001), operating and display units with part number 8L0 820 043 and indices "M" (or "N" for Japan)
will be installed until production has been reorganised.
=> Electrical System; Repair group 01
=> Parts List
◆ Control unit identification 8L0 820 043 X A3 or A4 Fully automatic air conditioner (depending on the code,
assignment=> Parts List).
=> Parts List
◆ Coding XXXXX =>Page 27
◆ WSC ZZZZZ is the workshop code for V.A.G 1551 that was used to perform the previous encoding.
◆ DXX designates the software version of operating and display unit -E87 and has no relevance for customer
service.
List of functions Page
01 - Interrogate control unit version 4
02 - Interrogate fault memory 7
03 - Final control diagnosis 18
04 - Basic setting 24
05 - Erase fault memory 26
06 - End output 26
07 - Encoding control unit 27
08 - Reading measured value block 31
Only the functions listed above can be used for the self-diagnosis of the electronic climate/heating control.
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
6 01 - Self-diagnosis, Electrical check

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
- Press ⇒key.
-> Indicated on display (selection of function, e.g. 02 - interrogate fault memory):
Rapid data transfer HELP
Select function XX
Notes:
◆ Pressing the HELP key prints a list of possible functions.
◆ Pressing the ⇒ key returns V.A.G 1551 program to its initial setting.
◆ If one of the following fault messages appears on the display:
-
Rapid data transfer HELP
No control unit response
-> Use the HELP key to print out the possible fault causes.
-
Rapid data transfer HELP
K-line not switched to positive
-> Check diagnostic connector wiringusing current flow diagram.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
->
Rapid data transfer
No signal from control unit
◆
Rapid data transfer
Communication problem
-> If this display appears at the start of or during the program, faults have occurred and data exchange is
no longer possible between the fault reader V.A.G 1551 and the control unit -E87. Check wiring of diagnostic
connector using the current flow diagram.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
- After eliminating the possible causes of trouble, enter address word 08 again for "Electronic climate/heating
control" and confirm with Q key.
-> Display following input of the address word 08:
and the following display then appears:
Rapid data transfer
Tester transmits address word 08
-> The control unit identification, the code and the workshop code for the V.A.G 1551 are displayed:
8L0 820 043 X A3 Fully aut. air
cond. DXX
Code XXXXX WSC ZZZZZ
- Press ⇒key.
-> Indicated on display (selection of function, e.g. 02 - interrogate fault memory):
Rapid data transfer HELP
Select function XX
3 - Interrogating fault memory
3.1 - Interrogating fault memory
- Connect fault reader V.A.G 1551,
Enter address word 08 "Electronic climate/heating control" and advance the program until "Select function
XX" appears on display (=>as of Page 4 ).
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
2.1 - Connecting vehicle diagnosis, measurement and information system VAS 5051 or
fault reader V.A.G 1551 and selecting function 7

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
- Switch on printer by pressing PRINT key (lamp in key lights up).
-> Indicated on display (function selection):
Rapid data transfer HELP
Select function XX
- Press keys 0 and 2. (02 selects the "Interrogating fault memory" function.)
-> Indicated on display:
Rapid data transfer Q
02 - Interrogate fault memory
- Press Q to confirm entry.
-> The number of stored faults or "No fault identified" is indicated on the display.
X faults detected
No faults detected
- Press ⇒key.
The stored faults are displayed and printed out one after the other.
- After the last fault has been displayed and printed out, rectify the faults in line with the fault table
(=>Page 9 ).
As with "No faults detected" the program returns to its initial position when the ⇒key is pressed.
-> Indicated on display (function selection):
Rapid data transfer HELP
Select function XX
- End output (function 06) =>Page 26
- Switch off ignition and detach diagnostic connector.
Notes:
◆ If a fault was detected:
- 1. Rectify fault.
- 2. Interrogate fault memory (function 02).
- 3. Erase fault memory (function 05).
- 4. Check code (function 01) or encode control unit (function 07).
- 5. Perform basic setting (function 04).
- 6. Interrogate fault memory (function 02) and erase if applicable (function 05).
- 7. End output (function 06).
◆ If no faults have been detected and complaints have been received about the air conditioner (e.g. the com‐
pressor is not functioning or only functioning intermittently, system control unsatisfactory, fresh air blower
speed cannot be regulated):
- 1. Read measured value block (Function 08) =>Page 31 .
- 2. Perform final control diagnosis (function 03) =>Page 18 .
- 3. Check refrigeration capacity of air conditioner=> Page 186 .
◆ If, when the ignition is switched on, no "Signal for ignition off time" has been detected by operating and
display unit -E87, the -E87 assumes a standing time of more than 4 hours and it is assumed that the engine
temperature is the same as the ambient temperature. It can happen when operating the heater that there
is a delay before the fresh air blower starts, even though the engine has reached operating temperature
(=>Page 31 Reading measured value block). The ambient temperature indicator -G106 in the dash panel
insert may display incorrect ambient temperature values.
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
8 01 - Self-diagnosis, Electrical check

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
◆ If the two display zones in the operating and control unit -E87 are not illuminated when the ignition is switched
on, rectify voltage supply from terminals 58, 58d and 58s (dimming) to -E87 according to the current flow
diagram =>Page 46 (Electrical check).
4 - Fault table
4.1 - Fault table
Notes:
◆ Listed below in ascending order of fault codes are all the faults detected by air conditioner operating and
display unit -E87 and displayed on V.A.G 1551.
◆ Faults are displayed as being sporadic if they only occur from time to time or if the fault memory has not
been erased following fault remedy. (The content of the fault memory is retained until it is erased, "non-
volatile memory".)
◆ In "Rapid data transfer" mode the fault code and flash code (for individual components only) only appear on
the printout.
Example:
Fault code Flash code
5-digit 4-digit
00532 2232
◆ An indication of the type of fault may also appear in the fault table (a display marked * appears, as well as
the component concerned or the "info" display).
◆ Once repairs have been completed, the fault memory is always to be interrogated again with fault reader
V.A.G 1551 and erased.
◆ Before replacing components, always check the relevant positive and earth connections (terminals 15, 75,
30 and 31), as well as all connectors (between -E87 and the component detected as being defective),
according to the current flow diagram.
◆ With all sporadic faults, it is particularly important to check the connectors for possible loose contacts.
◆ After replacing a component of the air conditioner/heating system, the basic setting (function 04) must always
be performed and then the fault memory read out and any faults indicated rectified and erased from the
memory (functions 02 and 05).
◆ Use test box V.A.G 1598/11 and V.A.G 1598/12 for checking the electrical connections of operating and
display unit -E87 in line with the current flow diagram.
◆ If the operating and display unit -E87 remains in operation after switching off the ignition, check wiring to -
E87, (plug -D- contact -1- in model with two displays or plug -D- contact 10 in model with one display) for
"short to positive" according to current flow diagram.
◆ If a fault is detected on the potentiometer in one of the air distribution positioning motors, the air distribution
can be influenced by actuating the keys on operating and display unit -E87.
◆ The display is switched from °C (Celsius) to °F (Fahrenheit) and vice versa by actuating the "Temperature
+" key when the "Air recirculation key" is pressed.
◆ If problems have been reported with the AC/heating electronics but no faults can be detected, perform
functions
"Final control diagnosis 03" and "Reading measured value block 08".
◆ Check refrigeration capacity of air conditioner =>Page 186 .
V.A.G 1551 printer Possible causes of fault Fault remedy
00000
No faults detected If "No faults detected" appears after performing repairs, the self-diagnosis is completed.
00532 2234
Power supply
* Signal too low /SP
- Voltage dips in electrical system to values
below 9.5 V 1)
Contact resistance in the wiring to -E87 (ter‐
minal 15 or 31).
- Check alternator and voltage regulator.
=> Electrical System; Repair group 01
Use current flow diagram to locate and elim‐
inate contact resistance.
1) If the vehicle's voltage drops to a value below 9.5 V, the compressor is switched off for at least 25 s. It is
switched back on only when the voltage exceeds a value of 10.8 V.
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
3.1 - Interrogating fault memory 9

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
V.A.G 1551 printer Possible causes of fault Fault remedy
00600
Potentiometer G92 in positioning
motor -V68 (for temperature flap) 1)
* Short to earth/SP
* Open circuit/short to
positive /SP
* Adaptation limit exceeded 2)
- Short circuit, open circuit in wiring
or fault in pin assignment of con‐
nectors between -G92 and -E87.
Temperature flap stiff.
Potentiometer -G92 in -V68 defec‐
tive
- Use current flow diagram to locate
and eliminate short circuit, open cir‐
cuit in wiring or fault in pin assign‐
ment.
Check freedom of movement of tem‐
perature flap3)
Replace positioning motor -V68.
00601
Potentiometer -G112 in positioning
motor -V70 (for central flap)
* Short to earth/SP
* Open circuit/short to
positive /SP
* Adaptation limit exceeded 2)
- Short circuit, open circuit in wiring
or fault in pin assignment of con‐
nectors between -G112 and -E87.
Central flap stiff.
Potentiometer -G112 in -V70 defec‐
tive
- Use current flow diagram to locate
and eliminate short circuit, open cir‐
cuit in wiring or fault in pin assign‐
ment.
Check freedom of movement of cen‐
tral flap3).
Replace positioning motor -V70
1) In the event of a fault at potentiometer -G92, positioning motor -V68 can be adjusted manually by actuating
the "+" or "-" key for temperature selection (display range between 0°C and 50 °C).
2) This fault is only detected during basic setting.
3) Both end stops must be reached.
V.A.G 1551 printer Possible causes of fault Fault remedy
00602
Potentiometer -G114 in positioning
motor -V85 (for footwell/defroster
flap)
* Short to earth/SP
* Open circuit/short to
positive /SP
* Adaptation limit exceeded 1)
- Short circuit, open circuit in wiring
or fault in pin assignment of con‐
nectors between -G114 and -E87.
Footwell/defroster flap stiff.
Potentiometer -G114 in -V85 de‐
fective.
- Use current flow diagram to locate
and eliminate short circuit, open cir‐
cuit in wiring or fault in pin assign‐
ment.
Check freedom of movement of
footwell/defroster flap2).
Replace positioning motor -V85.
00603
Footwell/defroster flap positioning
motor -V85
* Blocked or de-energised /SP
- Short circuit, open circuit in wiring
or fault in pin assignment of con‐
nectors between -V85 and
-E87.
Footwell/defroster flap stiff.
Positioning motor -V85 defective.
- Use current flow diagram to locate
and eliminate short circuit, open cir‐
cuit in wiring or fault in pin assign‐
ment.
Check freedom of movement of
footwell/defroster flap.
Check positioning motor -V85 (=>
Final control diagnosis, Page
18 ).
1) This fault is only detected during basic setting.
2) Both end stops must be reached.
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
10 01 - Self-diagnosis, Electrical check

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
V.A.G 1551 printer Possible causes of fault Fault remedy
00604
Potentiometer -G113 in positioning
motor -V71 (for air flow flap) 1)
* Short to earth/SP
* Open circuit/short to
positive /SP
* Adaptation limit exceeded 2)
- Short circuit, open circuit in wiring
or fault in pin assignment of con‐
nectors between -G113 and -E87.
Air flow flap or fresh/recirculated air
flap stiff.
Potentiometer -G113 in -V71 defec‐
tive.
- Use current flow diagram to locate
and eliminate short circuit, open cir‐
cuit in wiring or fault in pin assign‐
ment.
Check air flow valve and fresh/recir‐
culated air flap3) for ease of move‐
ment.
Replace positioning motor -V71.
1) This positioning motor actuates the fresh/recirculated air flap in addition to the air flow flap.
2) This fault is only detected during basic setting.
3) Both end stops must be reached.
V.A.G 1551 printer Possible causes of fault Fault remedy
00606
Two-way valve for refrigerant shut-
off valve -N147 1)
▪ In the event of an-E87 with two
displays
Fault not intended
*Short to earth/SP
*Open circuit/short to
positive /SP
▪ In vehicles without map-controlled
engine cooling and one -E87 with
one display
Wrongly coded operating and dis‐
play unit -E87
Check and correct coding of -E87
(=> Page 27 ).
▪ In vehicles with map-controlled en‐
gine cooling and one -E87 with one
display
Wrongly coded operating and dis‐
play unit -E87
Short circuit or open circuit between
-N147 and -E87.
Two-way valve -N147 defective.
Checking and correcting coding of -
E87 (=> Page 46 ).
1) The two-way valve -N147 is only installed in vehicles with map-controlled engine cooling and one operating
and display unit -E87 with one display.
V.A.G 1551 printer Possible causes of fault Fault remedy
00625
Vehicle speed signal
* Implausible signal /SP
- Loose contact in the wiring be‐
tween road speed sender -G68,
dash panel insert or another com‐
ponent also connected to this signal
(e.g. radio or cruise control unit) and
-E87.
Invalid signal from speedometer -
G21/dash panel insert, or another
connected component destroys the
signal.
- Use current flow diagram to locate
and eliminate loose contact:
Check road speed signal from sender
-G21 or from the dash panel insert
(note all the components connected
to this signal wire).
=> Electrical System; Repair group
90
00779 3133
Ambient temperature sensor -G17
*Short to earth/SP
*Open circuit/short to
positive /SP
- Short circuit or open circuit be‐
tween -G17 and -E87.
Temperature sensor -G17 defec‐
tive.
- Use current flow diagram to locate
and eliminate short circuit or open cir‐
cuit
Check temperature sensor -G17
(=>Electrical check, Page 46 ).
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
4.1 - Fault table 11

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
V.A.G 1551 printer Possible causes of fault Fault remedy
00785 3211
Dash panel temperature sensor -
G56
* Short to earth/SP
* Open circuit/short to
positive /SP
▪ In the event of an -E87 with two
displays
Short circuit or open circuit be‐
tween -G56 and -E87.
Temperature sensor -G56 defec‐
tive.
▪ In the event of an -E87 with two dis‐
plays
Use current flow diagram to locate
and eliminate short circuit or open cir‐
cuit
Checktemperature sensor -G56
(=>Electrical check, Page 46 ).
▪ In the case of an -E87 with one
display:
Operating and display unit -E87 de‐
fective.
▪ In the case of an -E87 with one dis‐
play:
Renew operating and display unit -
E87.
00787 3213
Temperature sensor for fresh air in‐
take duct -G89
* Short to earth/SP
* Open circuit/short to
positive /SP
- Short circuit or open circuit be‐
tween -G89 and -E87.
Temperature sensor -G89 defec‐
tive.
- Use current flow diagram to locate
and eliminate short circuit or open cir‐
cuit
Checktemperature sensor -G89
(=>Electrical check, Page 46 ).
Vehicles with air conditioner pressure switch -F129
V.A.G 1551 printer Possible causes of fault Fault remedy
00792 3224
Air conditioner pressure switch -
F129
* Short to earth /SP
- Open circuit in wiring between -
F129 and -E87.
Actuation of radiator fan -V7 (speed
1) defective.
Condenser or radiator dirty.
Actuation of radiator fan -V7 (speed
2) from pressure switch -F129 de‐
fective.
Pressure switch -F129 defective.
Fault in refrigerant circuit (overpres‐
sure or vacuum).
- Use current flow diagram to locate
and eliminate open circuit or loose
contact.
Check the actuation of the fan -V7
(speed 1) =>Final control diagnosis,
Page 135 ).
Send vehicle to a specialist VW/Audi
air-conditioning service centre.
Notes:
◆ High-pressure sensor -G65 will gradually replace air conditioner pressure switch -F129 (as of Model Year
1999, initially vehicles with 1.6 l engines). As of model year 2001 only high pressure switches -G65 are
installed.
◆ Radiator fan control unit -J293 versions and vehicle wiring differ for vehicles with pressure switch -F129 and
high-pressure sensor -G65.
=> Parts List
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
◆ Pressure switch -F129 consists of 2 switching elements:
- The compressor is switched off via contacts 1 and 2 in the event of vacuum or overpressure in the refrigerant
circuit (switch opens).
- The radiator fan is switched to the 2nd speed via contacts 3 and 4 (switch closes).
◆ If the switch between contacts 1 and 2 in pressure switch -F129 is open, this is initially recognised by
operating and display unit -E87 as overpressure in the refrigerant circuit and stored as a fault. If the measured
ambient temperature is between 0 °C and 50 °C and the switch remains open for longer than 30 seconds,
the function switches from overpressure to vacuum pressure (low-pressure switch function) =>Reading
measured value block, Page 31 (display group 01, compressor shut-off criteria).
◆ If open high-pressure switch -F129 is detected 30 times within one driving period due to a loose contact, for
example, the compressor is switched off. The compressor can be switched on again by actuating the "Com‐
pressor on" button or by switching the ignition off and on again. If this fault occurs over several driving cycles,
the compressor cannot be switched on again until the fault memory has been erased.
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
12 01 - Self-diagnosis, Electrical check

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
Vehicles with high-pressure sensor -G65
V.A.G 1551 printer Possible causes of fault Fault remedy
00792 3224
Air conditioner pressure switch -
F129
* Short to earth /SP
- Open circuit in the wiring between
radiator fan control unit -J293 and -
E87.
Open circuit in the wiring between
High-pressure sensor -G65 and
control unit -J293.
- Use current flow diagram to locate
and eliminate open circuit or loose
contact.
=> Current Flow Diagrams, Electrical
Fault-Finding and Fitting Locations
(cont.)
▼
V.A.G 1551 printer Possible causes of fault Fault remedy
(cont.) - Open circuit in the power supply or in the
earth connection to high-pressure sensor -
G65.
Short circuit in the wiring between -G65, -
J293 and the engine control unit
- Use current flow diagram to locate and elim‐
inate open circuit or loose contact.
=> Current Flow Diagrams, Electrical Fault-
Finding and Fitting Locations
Use current flow diagram to locate and elim‐
inate short circuit
- Actuation of radiator fan -V7 (speed 1) de‐
fective.
Condenser or radiator dirty.
Actuation of radiator fan -V7 (speed 2) by
radiator fan control unit -J293 defective
- Check the actuation of the fan -V7 (speed
1) =>Final control diagnosis, Page 46 ).
(cont.)
▼
V.A.G 1551 printer Possible causes of fault Fault remedy
(cont.) - High-pressure sensor -G65 defective.
Radiator fan control unit -J293 defective.
Fault in refrigerant circuit (overpressure or
vacuum).
- Check signal from high-pressure sensor -
G65 (=>Page 76 ).
Send vehicle to a specialist VW/Audi air-con‐
ditioning service centre.
Notes:
◆ High-pressure sensor -G65 will gradually replace air conditioner pressure switch -F129 (as of model year
1999, initially vehicles with 1.6 l engines). As of model year 2001 only high-pressure switches -G65 are
installed.
◆ Radiator fan control unit -J293 versions and vehicle wiring differ for vehicles with pressure switch -F129 and
high-pressure sensor -G65.
=> Parts List
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
◆ The high-pressure sensor -G65 generates a square wave-signal whose duty cycle changes in line with the
refrigerant circuit pressure =>Page 85
◆ Depending on high-pressure sensor -G65 signal, radiator fan control unit -J293:
- indicates to operating and display unit -E87 that the refrigerant circuit pressure is OK and the compressor
can be switched on (magnetic clutch -N25 via control unit -J293).
- switches radiator fan to 2nd speed if pressure increases.
◆ The signal generated by high-pressure sensor -G65 is also used for engine control (the required compressor
drive torque is governed by the refrigerant circuit pressure). Depending on the engine control unit version,
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
4.1 - Fault table 13

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
the measured value block signal is displayed as a duty cycle (e.g. for 1.61 aluminium engine in measured
value block 57, display zone 4).
=> Relevant Workshop Manual Injection and Ignition system
◆ If within one driving period an excessively high pressure is measured 30 times in the refrigerant circuit and
the compressor (magnetic clutch -N25) is switched off by operating and display unit -E87, the compressor
no longer switches on automatically. The compressor can be switched on again by actuating the "Com‐
pressor on" button or by switching the ignition off and on again. If this fault occurs over several driving cycles,
the compressor cannot be switched on again until the fault memory has been erased.
V.A.G 1551 printer Possible causes of fault Fault remedy
00796 3234
Dash panel temperature sensor
blower -V42
* Blocked or de-energised /SP
- Open circuit in the power supply
to -V42 or in the wiring between -
V42 and -E87.
Blower -V42 defective.
- Locate and eliminate the open cir‐
cuit using the current flow diagram
Replace blower -V42.
00797 3241
Sunlight penetration photo sensor -
G107
* Open circuit/short to
positive /SP
* Short to earth /SP
- Short circuit or open circuit be‐
tween -G107 and -E87.
Photosensor -G107 defective.
- Use current flow diagram to locate
and eliminate short circuit, open cir‐
cuit in wiring or fault in pin assign‐
ment.
Replace photosensor -G107 .
00818
Evaporator outlet temperature send‐
er -G263
* Short to earth /SP
* Open circuit/short to
positive /SP
- The sender -G263 is not installed
in the Audi A3 at the moment.
Short circuit to connector B contact
15 at -E87.
- Use current flow diagram to locate
and eliminate short circuit
Notes:
◆ With operating and display units -E87 with one display the blower -V42 is installed into -E87.
◆ The fault "sender for ambient temperature evaporator -G263" can only be displayed by an operating and
display unit -E87 with one display.
V.A.G 1551 printer Possible causes of fault Fault remedy
Operating and display unit up to index "E" (two displays)
01044
Control unit incorrectly encoded - Proper encoding procedure for -E87
was not followed
Wrong code was entered
- Code operating and display unit -E87
as specified =>Page 27
(cont.)
▼
Note:
The faults "Control unit incorrectly encoded" and "Basic setting not performed" are not stored by all operating
and display unit versions (operating and display units that store these faults are gradually introduced as of
Model Year 1999).
V.A.G 1551 printer Possible causes of fault Fault remedy
(cont.) Operating and display unit -E87 with index "M" or "N" (two displays)
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
14 01 - Self-diagnosis, Electrical check