wiring AUDI A4 1996 B5 / 1.G ATQ Engine Tank Ventilation Checking Workshop Manual

24-131

Checking voltage supply

Test requirements:

Fuse for the EVAP valve OK.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

Fuel Pump (FP) OK, checking Page 24
-
49
.

Note:
Voltage is supplied to the EVAP valve via the
Fuel Pump (FP) relay.

- Disconnect connector at EVAP valve.

- Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
1 Engine Ground (GND)
- Operate starter briefly (engine can also start).

LED must light up.
Pa
ge 5 of 7 Tank ventilation, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.4

24-132
If LED does not light up:

- Check wire connection from terminal 1 to Fuel
Pump (FP) relay via fuse for open circuit.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
- Repair open circuit if necessary.
If LED lights up:

- Checking activation.

Checking activation

- Connect VAG1527B voltage tester to connector terminals 1 (B+) and 2.
- Initiate output DTM and activate Evaporative Emission (EVAP) canister
purge regulator valve -N80- Page 01
-56
.

LED must blink.
Pa
ge 6 of 7 Tank ventilation, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.4

24-133
If LED does not blink or if it remains constantly
lit:

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

If wire connection is OK: - Check the following wire connection for open circuit and short circuit to
Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
2 64
- Repair open circuit or short circuit if necessary.
- Replace Engine Control Module (ECM) Page 24
-21
.
Pa
ge 7 of 7 Tank ventilation, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.4