AUDI A8 1999 D2 / 1.G AHA Engine Auxiliary Signals Checking Workshop Manual
A8 1999 D2 / 1.G
AUDI
AUDI
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AUDI A8 1999 D2 / 1.G AHA Engine Auxiliary Signals Checking Workshop Manual
Page 5 of 22
Notes:
The A/C compressor is switched off during
acceleration when the car is stationary or at
slow speed.
At wide open throttle the A/C compressor is
switched off by the Transmission Control
Module (TCM) (via the kick down switch).
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Page 6 of 22
24-167
Continuation
If the displayed values are NOT OK:
- Connect VAG1598/22 test box to ECM harness
connector page 01
-67
.
- Check wiring for open circuit, short circuit to B+
or short circuit to Ground between ECM/test box
terminal 8 and either A/C control head -E87- or
Transmission Control Module (TCM).
Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder If the wiring is OK:
- Check function of A/C control head -E87-.
Repair Manual, Heating & Air Conditioning,
Repair Group 01
- Carry out electrical testing of automatic
transmission.
Repair Manual, 5 Spd. Automatic
Transmission 01V, Repair Group 01
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Page 9 of 22
Read safety precautions for test driving vehicles
while using test equipment page 24
-9 .
The speed signal is generated by the vehicle
speed sensor (at the transmission), and
processed at the speedometer/odometer in the
instrument cluster.
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Page 15 of 22
24-172
CAN-Bus, checking
When a CAN-Bus malfunction is indicated during
a check of DTC memory of the Engine Control
Module (ECM), refer to the following test to
eliminate the malfunction.
Note:
The information exchange occurs between the
Engine Control Module (ECM) and the
Transmission Control Module (TCM) via a CAN-
Bus.
All signals are carried by 2 wires between the
ECM and the TCM.
Required special tools and test equipment
VAG1551 or VAG1552 Scan Tool (ST) with
VAG1551/3 adapter cable
VAG1598/22 test box
VW1594 connector test kit
Wiring diagrams
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Page 16 of 22
24-173
Checking
- Check DTC memory of Transmission Control
Module (TCM).
Repair Manual, 5 Spd. Automatic
Transmission 01V, Repair Group 01 If a DTC regarding the CAN-Bus wire is also
stored in the TCM:
- Switch ignition off.
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder
If wiring is OK: - Connect VAG1598/22 test box to ECM harness connector page 01
-
67
.
- Check wires from terminal 29 and terminal 41 of test box to
transmission control module for open or short circuit per wiring
diagram. - Replace Transmission Control Module (TCM) and Engine Control
Module (ECM) as necessary and in sequence.
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