ABS AUDI A4 1995 B5 / 1.G APB Engine Additional Signals Checking Workshop Manual

24-198

Signal for rough road recognition from
ABS/EDL control module, checking


Note:

The ABS/EDL control module generates the
rough road signal if it recognizes wheel spin on
a wheel. The Engine Control Module (ECM)
switches off the misfire recognition once the
rough road signal is recognized by the ECM.
The rough road signal should only be checked if
the malfunction (P1606) 18014 "Rough Road
Spec Engine Torque ABS-ECU/Electrical
Malfunction" is stored in the DTC memory. It is
possible that the malfunction "Misfiring" is also
stored in DTC memory, however this is then a
sequence error and should be ignored.
The wiring and the rough road signal is
monitored by the ECM.
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24-199

Test conditions

Control module coding OK Page 01
-93
.

Test sequence

- Connect VAG1598/31 test box to wiring harness
for engine control module. Do not connect to the
engine control module itself Page 24
-20
.

- Check wire from test box socket 74 to ABS
Control Module according to wiring diagram for
short circuit or open circuit.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
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24-200
If no malfunction is detected:

- Replace ABS control module.
If, after the ABS control module has been
replaced the malfunction appears again:

- Replace Engine Control Module (ECM) Page
24
-24
.
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24-201

Data exchange between Engine/ABS/
Transmission control module, checking


Notes:

The data exchange between the various control
modules is carried out via a bus system.
The term "Bus" refers to a system for
transmitting and distributing data.
The wires which connect the control modules
and convey the data between them are called
data wires.
Data is transmitted via data wires in serial, i.e.
in a specific order to the connected control
modules.
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24-203

Read measuring value block 125
1
2
3
4

When indicated on display:
- Check indications in display fields 1 through 4.
CAN capable control modules connected to the Engine Control Module
(ECM) are indicated:

No indication (display field empty): Control module not CAN-
capable
Indication 1: CAN capable control module is connected to databus
Indication 0: CAN capable control module is not connected to
databus (e.g. in case of malfunction)
Read measuring value block 125
ABS 1
Combi 1

Example:
Note:
Display group 125 indicates all systems that communicate with the Engine
Control Module (ECM) via the CAN-bus. (In this example, the ABS control
module and the instrument cluster). If these systems are not installed, the
display fields in display group 125 that are intended for them will be
empty. Display field 1 will indicate "Transmission 1" and display field 4 will
indicate "A/C 1" if these systems are communicated with the Engine
Control Module (ECM) via the CAN-bus.
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