AUDI A3 1996 8L / 1.G ATW Engine Additional Signals User Guide

24-163

Wire for crash signal, checking

The Engine Control Module (ECM) receives the
crash signal ("Crash shut-off was triggered") from
the airbag control module.
When the airbag control module sends the crash
signal to the ECM (during an accident or when
output DTM is being performed for the airbag
system), the ECM switches the Fuel Pump (FP)
off. This means that the engine will stop running
but can be started again afterward (e.g. to
remove vehicle from danger).

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

- Check following wire connection for open circuit
and short circuit to Ground (GND) and B+:

Test box
VAG1598/31
Socket
Control module for
Airbag -J234-
Terminal
67 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations
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24-164

- Repair open circuit or short circuit if
necessary.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations If no malfunctions are found in wire:

- Check DTC memory of control module for
airbag:

Repair Manual, Body On Board Diagnostic
(OBD), Repair Group 01; OBD of airbag system BAE (basic trigger unit) with side airbag; DTC memory, checking

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24-165

Consumption signal for board
computer, checking


Note:

The consumption signal is calculated by the
ECM from the injection time and directed to the
board computer via terminal 81 of the ECM.
Consumption signal, checking

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
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24-166

Wire for fuel level signal, checking


Note:

The signal helps with cause localization when
certain malfunctions are recognized (e.g.
combustion misfires).
The processed signal enters at terminal 30 of
the ECM and is used to determine the cause of
certain recognized malfunctions (e.g.
combustion misfires).

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

- Check following wire connection for open circuit
and short circuit to Ground (GND) and B+:

Test box
VAG1598/31
Socket
Instrument cluster

Terminal
30 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations
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- Repair open circuit or short circuit if
necessary.
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24-167

Signal for rough terrain recognition,
checking


Note:

When the ABS/EDL control module recognizes
that a wheel is spinning, the ABS/EDL control
module generates the rough terrain signal.
When the Engine Control Module (ECM)
recognizes the rough terrain signal, combustion
misfire recognition is switched off in the Engine
Control Module (ECM).
Only check the rough terrain signal if the
malfunction "18014 (P1606) rough terrain
info/engine torque from ABS cont. mod.
Electrical malfunction in circuit" is stored DTC
memory. It is possible that the malfunction
"Combustion misfire" is also stored in DTC
memory as a side effect and it can be
disregarded.
The wire connection and rough terrain signal
are monitored by the Engine Control Module
(ECM).
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24-168

Test requirement:

Control module coding OK Page 01
-62
.

Test sequence

- Switch ignition off.

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

- Check following wire connection for open circuit
and short circuit to Ground (GND) and B+:

Test box
VAG1598/31
Socket
ABS control module (w/EDL)
-J104-
Terminal
74 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations
If no malfunctions are found in wire:

- Replace ABS control module.
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If the malfunction is indicated again after
replacing the ABS control module:

- Replace Engine Control Module (ECM) Page
24
-23

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24-169

Data transfer between Engine Control
Module (ECM) and CAN-capable control
modules, checking


Note:

Data exchange between individual control
modules occurs via a bus system.
The term "CAN-bus" refers to a system that
transports and distributes data.
The wire connections between the control
modules, via which data is transferred, are
referred to as data wires.
Data is transferred to the connected control
modules serially (one after the other) via these
data wires (i.e. engine speed, accelerator
position).

Checking bus system
The DTC table suggested checking the data
exchange between the Engine Control Module
(ECM) and CAN capable control modules.

-
Connect VAS5051 tester or VAG1551 scan tool
and select control module for engine electronics
using "address word" 01 Page 01
-10
. Ignition
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must remain switched on.
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