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

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.
1.3 - 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

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.
1.4 - 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

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.
1.6 - 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