1999 AUDI A4 engine

24-13


The following harness connectors are located below the coolant
expansion tank: Fig. 1 Installation location, harness connectors
1 - 4-pin harness connector, brown
for Oxygen Sensor (O2S) behind Three Way Catalytic Converter
(TWC) -G130- and Oxygen Sensor (O2S) Heater 1 -Z29- (bank 1
sensor 2)
2 - 6-pin harness connector, black
for Heated Oxygen Sensor (HO2S) -G39- before catalytic converter
and Oxygen Sensor (O2S) Heater -Z19- (bank 1 sensor 1)
3 - 3-pin harness connector, gray
for Engine Speed (RPM) sensor -G28-
4 - 3-pin harness connector, blue
for Knock Sensor (KS) 2 -G66-
5 - 3-pin harness connector, green
for Knock Sensor (KS) 1 -G61-

Fuel Pump (FP) Relay -J17- is located at position 4 of central electrics in
driver's footwell, left. Fig. 2 Component locations Fuel Pump (FP) Relay -J17-
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24-15


Fig. 5 Installation position, Throttle Position (TP) sensor -G79-
and sender 2 for accelerator pedal position -G185-

Fig. 6 Installation positions in E-box, plenum chamber
1 - Engine Control Module (ECM)
2 - Secondary Air Injection (AIR) pump relay -J299-
3 - Motronic Engine Control Module (ECM) power supply relay -J271-
4 - Installation location of fuse S130 for Secondary Air Injection (AIR)
pump
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24-19

Wiring and component testing using
VAG1598/31 test box


Note:

VAG1598/31 test box is designed so that it can
be simultaneously connected to the wiring
harness at the Engine Control Module (ECM)
and also to the ECM itself.
This is advantageous because electronic
engine control remains fully functional (e.g.
measurement of signals with engine running)
when the test box is attached.
Relevant test procedures note whether Engine
Control Module (ECM) should also be
connected to the test box or not.
Always use VAG1594A connector test kit to
attach measurement devices (e.g. VAG1527B
voltage tester, VAG1526 multimeter etc.).

WARNING!

To avoid damaging electronic components,
set measuring range before connecting test
leads and observe all test requirements.
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24-20

Special tools and equipment

Procedure
VAG1598/31
- Switch ignition off.
- Remove Engine Control Module (ECM) Page 24
-23
.

- Connect VAG1598/31 test box to connector of wiring harness. Ground
(GND) clip at test box (not visible in illustration) must be connected to
Ground (GND). Relevant test procedures note whether Engine Control
Module (ECM) should also be connected to the test box.
- Perform test as described in relevant repair sequence.
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24-21

Note:
Important note:
After re-connecting the Engine Control Module
(ECM), the following work steps must be
performed:
- Perform adaptation of the Throttle Valve Control
Module -J338- Page 24
-121
.
- For vehicles with automatic transmission, the
kick down function must be adapted Page 24
-
139
.
- Check DTC memory and erase it if necessary
Page 01
-16
.
- If DTC memory was erased, readiness code
must be re-generated Page 01
-73
.

Note:
During the first adaptation phase, it is possible
that idle will be rough and vehicle may shake
lightly in drive mode.
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24-23

Engine Control Module (ECM), replacing


Special tools and equipment

or
Removing
VAS5051 with VAG5051/1VAG1551 with VAG1551/3A
- Connect VAS5051 tester or VAG1551 scan tool and select control
module for engine electronics using "address word" 01 Page 01
-10
.
Ignition must remain switched on.
4B0906018Q
1.8 L R4/5VT
G 0008
Codin
g 07551
WSC 12345

VAG1551 Scan Tool (ST) display indicates control module identification,
e.g.
- Always allow display of control module identification first and print it out
Page 01
-13
.
- Compare coding with coding versions Page 01
-64
.
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24-25


- Using a screwdriver, carefully pry off retaining bracket (arrow).

Note:
Adaptation values are erased when connector is disconnected from the
Engine Control Module (ECM), DTC memory content remains intact. - Disengage connector catches (arrows) and disconnect harness
connectors -1- and -2- from control module.
- Remove Engine Control Module (ECM).
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24-26

Installing
Installation is reverse of removal, noting the
following:

Note:
Important note:
After installing new Engine Control Module
(ECM), the following work steps must be
performed:
- Check DTC memory and erase it if necessary
Page 01
-16
.
- Perform adaptation of the Throttle Valve Control
Module -J338- Page 24
-121
.
- Observe notes for coding new Engine Control
Module (ECM) Page 01
-62
.
- For vehicles with cruise control (discernable at
steering column), switch this free in ECM:

Repair Manual, Electrical Equipment On
Board Diagnostic (OBD), Repair Group 01; OBD for cruise control system

- For vehicles with automatic transmission, the
kick down function must be adapted Page 24
-
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