Canister Purge Control Valve: Testing and Inspection

Special Tools And Equipment







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 auxiliary hose to one connection of EVAP valve.
- Connect VAS5051 tester or VAG 1551 scan tool and select control module for engine electronics using "address word" 01.
- Ignition must remain switched on for this.
- Initiate output DTM and activate Evaporative Emission (EVAP) canister purge regulator valve - N80 - (tank ventilation valve).

Indicated on display:


Output Diagnostic Test Mode ->
EVAP canister purge regulator valve - N80


- Valve must click...
- ...and must open and close (can be tested by blowing into auxiliary hose).

If valve does not click:
- Check internal resistance of EVAP valve.

If valve does not open and close properly:
- Replace Evaporative Emission (EVAP) canister purge regulator valve - N80 -

Checking internal resistance
- Disconnect connector at EVAP valve.







- Connect multimeter at valve for resistance measurement.
- Specified value: 22 - 30 ohm

If specified value is not obtained:
- Replace Evaporative Emission (EVAP) canister purge regulator valve - N80 -.

If specified value is obtained:
- Check voltage supply.







Checking voltage supply


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


Test requirement
- Fuse for the EVAP valve OK
- Disconnect connector at EVAP valve.
- Connect VAG 1527B voltage tester as follows:

Harness connector terminal Measure to
1 Engine Ground

- Operate starter briefly.
- LED must light.

If LED does not light:
- Check wire connection from terminal 1 to Fuel Pump (FP) relay via fuse for open circuit.
- Repair open circuit if necessary.

If wire connection is OK:
- Check Fuel Pump (FP) relay. Testing and Inspection

If LED lights:
- Checking activation.

Checking activation
- Connect VAG 1527B voltage tester to connector terminals 1 (B+) and 2.
- Initiate output DTM and activate Evaporative Emission (EVAP) canister purge regulator valve - N80 -.
- LED must blink

If LED does not blink or it it remains constantly lit:
- Connect VAG 1598/31 test box at wiring harness to ECM, do not connect ECM.
- Check the following wire connection for open circuit and short circuit to Ground and B+:

Harness connector terminal VAG 1598/31 test box socket
2 64

- Repair open circuit or short circuit if necessary.

If wire connection is OK:
- Replace Engine Control Module (ECM).