1998 AUDI A4 AHA Engine Auxiliary Signals Checking Workshop Manual

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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24-176

Fuel level signal, checking


Notes:

If there is too little fuel in the fuel reservoir (less
than 2 gallons) combustion misfiring and/or fuel
system malfunctions could occur. In this case
the malfunction "Fuel level too low" is stored in
the DTC memory (SAE P1250 / VAG 17658).
This malfunction always occurs with
combustion misfiring or fuel system
malfunctions.
In general eliminate all other malfunctions
first.

- Fill fuel tank of vehicle (at least 20 ltr, or 5.25
gal).

- Check and then erase DTC memory page 01
-
16
.

- Check readiness code page 01
-70
.

- Generate new readiness code page 01
-73
.
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24-177

- Conduct a test drive ( Safety precautions
page 24
-9 ).

- Check DTC memory of ECM page 01
-16
.
If only the DTC "Fuel level too low" (SAE P1250 /
VAG 17658) is stored in the DTC memory.

Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect VAG1598/22 test box to ECM harness connector page 01
-
67
.
- Check wire from terminal 21 of test box to instrument cluster for open
circuit or short circuit per wiring diagram.
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