diagram AUDI A4 1999 B5 / 1.G AEB Engine Additional Signal

24-145


Additional signals

Signal from A/C compressor, checking


Required special tools and test equipment

VAG 1551 or VAG 1552 Scan Tool (ST) with
VAG 1551/3 adapter cable
VAG 1598/22 test box
Multimeter US 1119 (Fluke 83 or equivalent)
VW 1594 connector test kit
Wiring diagrams

Test conditions
A/C functions OK
A/C is switched off
Vehicle at room temperature-above 15 C
(59 F)

No malfunctions stored in Diagnostic Trouble
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Continuation
If the displayed values are NOT OK:

- Connect VAG 1598/22 test box to ECM harness
connector Page 01
-56
.

- Check wiring for open circuit, short circuit to B+
or short circuit to Ground between ECM/test box
terminal 8 and A/C control head -E87-, or
Transmission Control Module (TCM).

Electrical Wiring Diagrams, Troubleshooting &
Component Locations If the wiring is OK:

- Check function of A/C control head -E87-.

Repair Manual, Heating & Air Conditioning,
Repair Group 01

Or:

Repair Manual, 5 Spd. Automatic
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Vehicle speed signal, checking


Required special tools and test equipment

VAG 1551 or VAG 1552 Scan Tool (ST) with
VAG 1551/3 adapter cable
Multimeter US 1119 (Fluke 83 or equivalent)
VW 1594 connector test kit
Wiring diagrams

Test conditions
Vehicle Speed Sensor (VSS) OK; checking:

Repair Manual, Electrical Equipment, Repair
Group 90


Notes:

To check Vehicle Speed Sensor -G68-, the
vehicle must be driven. A second technician is
required to operate the scan tool during the
road test.
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Continuation
If no speed was indicated:

Notes:
If the LED does not blink:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If the wiring is OK and the LED does not blink:
Repair Manual, Electrical Equipment, Repair Group 90
- Connect VAG 1598/22 test box to ECM harness connector Page 01
-
56
.
- Connect VAG 1527B 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
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Continuation

Note:
The wiring to the Transmission Control Module is
monitored by On Board Diagnostic and stores
the Diagnostic Trouble Code 00545 if there is a
malfunction.
If displayed value is NOT OK (not as specified),
or if DTC 00545 is stored in DTC memory:

- Connect VAG 1598/22 test box to ECM harness
connector Page 01
-56
.

Electrical Wiring Diagrams, Troubleshooting & Component Locations - Check wiring for short circuit or open circuit between ECM harness
connector terminal 23 and to Transmission Control Module (TCM),
according to wiring diagram
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Test requirements

ECM coding OK Page 01
-13


Test sequence

- Switch ignition off.

- Connect VAG 1598/22 test box to ECM harness
connector Page 01
-56
.

- Check signal wiring for short circuit or open
circuit between ECM/test box and ABS control
module, according to wiring diagram.
If the wiring is OK:

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

- Replace Motronic ECM -J220- Page 01
-57
.

- Carry out adaptation of throttle valve control
module to ECM Page 24
-119
.

-
Check readiness code Page 01
-59
. If
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