AUDI A8 1995 D2 / 1.G AHA Engine Auxiliary Signals Checking User Guide

24-170


Display fields

1 2 3 4
Display group 5: General engine data
Display xxx RPM xx.xx ms xxx km/h Idle
Part throt
Full throt
Decel
Enrich
Indicates Engine speed
(in 40 RPM
steps) Engine load Vehicle speed Operating
condition
Range 0 - 6800 RPM 0.00 - 12.75
ms 0 - 326 km/h ---
Specified
value --- --- Approx. vehicle speed ---

--- --- If no vehicle speed is displayed page 24
-171
,
Continuation
---
If displayed value is OK:

-
Press button.
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- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.

- Switch off ignition.
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Continuation
If no speed was indicated:

Notes:
If the LED does not blink:
If the wiring is OK and the LED does not blink:
Repair Manual, Electrical Equipment, Repair Group 90
- Connect VAG1598/22 test box to ECM harness connector page 01
-
67
.
- Connect VAG1527B LED voltage tester between ECM/test box sockets
3 (B+) and 20 (signal).
- Lift vehicle at left-front until wheel is free.
- Switch ignition on and rotate left-front wheel by hand.
LED must blink (very brief blink)
The right-front wheel must not rotate; block it if necessary.For LEDs with little voltage consumption, the LED lights up at half
strength when the ignition is switched on.
- Check wiring from ECM connector, terminal 20 to instrument cluster for
open circuit or short circuit Electrical Wiring Diagrams,
Troubleshooting & Component Locations binder.
-
Check readiness code page 01
-70
. If Diagnostic Trouble Code
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(DTC) memory has been erased, or ECM was disconnected, generate
new readiness code page 01
-73
.
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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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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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24-174

Rough road signal from ABS/EDL
control module, checking


Notes:

When the ABS/EDL control module senses a
wheel spinning, it produces the rough road
signal. When the ECM recognizes the rough
road signal, the misfire recognition is switched
off.
Check the rough road signal only when the
trouble code 18014 "Rough Road Spec Engine
Torque ABS-ECU Electrical Malfunction" is
stored. The possible "Misfire" malfunction is in
this case a subsequent malfunction that can be
disregarded.
The wiring and the rough road signal are
monitored by the ECM.
Emissions testing on a front-wheel drive vehicle
with ABS/EDL, during which only the front
wheels turn while the rear wheels are
stationary, can result in the DTC 18014 being
stored in DTC memory. Therefore, the fuse for
the ABS/EDL control module must be removed.
After the test, check DTC memory for the
ABS/EDL control module and the ECM. Then
erase DTC memory.
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Required special tools and test equipment

VAG1551 or VAG1552 Scan Tool (ST) with
VAG1551/3 adapter cable
VAG1598/22 test box
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24-175

Test requirements

ECM coding OK page 01
-14


Test sequence

- Switch ignition off.

- Connect VAG1598/22 test box to ECM harness
connector page 01
-67
.

Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder
If the wiring is OK:
If the malfunction occurs again after the ABS control module has been
replaced: - Check signal wiring between ECM/test box terminal 45 and ABS
control module for short circuit or open circuit. - Replace ABS control module.
- Replace Motronic ECM -J220- page 01
-68
.
- Carry out adaptation of throttle valve control module to ECM page
24
-150
.
-
Check readiness code page 01
-70
. If Diagnostic Trouble Code
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(DTC) memory has been erased, or ECM was disconnected, generate
new readiness code page 01
-73
.
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