AUDI A4 1995 B5 / 1.G AWM Engine Tank Ventilation Checking Workshop Manual

24-114


Tank ventilation, checking Evaporative Emission (EVAP) canister
purge regulator valve -N80-, checking

Special Tools and Equipment

VAG1526A
VAG1527B
VAG1594A
VAG1598/31
VAS5051 with VAG5051/1
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Checking for proper seal
When there is no current, the Evaporative
Emission (EVAP) canister purge regulator valve -
N80- is closed.

- Disconnect hoses from EVAP valve; harness
connector remains connected.

- Attach assisting hose to one connection of
EVAP valve.

- Connect VAS5051 tester Page 01
-7 and
select vehicle system "01 - Engine electronics".
Ignition must remain switched on for this.

- Initiate output DTM and activate Evaporative
Emission (EVAP) canister purge regulator valve
-N80- Page 01
-51
.

Display on VAS5051:
A - 1. Actuator in test
1 - EVAP canister purge regulator valve -N80-
Valve must click... ...and must open and close (can be tested by blowing into
assisting hose).
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24-116
If valve does not click:

- Check internal resistance of EVAP valve.
If valve does not open or close properly:

- Replace Evaporative Emission (EVAP) canister
purge regulator valve -N80-.

Checking internal resistance

- Disconnect connector at EVAP valve.

If specified value is not obtained:
If specified value is obtained: - Connect multimeter at valve for resistance measurement.

Specification: 22 to 30
- Replace Evaporative Emission (EVAP) canister purge regulator valve -
N80-.
- Check voltage supply Page 24
-117
.
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24-117

Checking voltage supply

Test requirements:

Fuse for the EVAP valve OK.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations

Fuel Pump (FP) relay OK; checking Page 24
-52
.

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.
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24-118
If LED does not light up:

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

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
- 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
-51
.

LED must blink.
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24-119
If LED does not blink or if it remains constantly
lit:

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

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
-22
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