Canister Purge Solenoid: Testing and Inspection

CHECKING THE CANISTER PURGE REGULATOR VALVE

NOTE:
For functional testing of Evaporative Emission Control (EVAP) canister purge regulator valve activation, also see On-Board Diagnostics, "Read Measuring Value Block" function 08. Testing and Inspection

ELECTRICAL CHECK
- Disconnect harness connector on EVAP canister purge regulator valve.

EVAP Canister Purge Regulator Valve Test:

- Measure valve resistance.
^ Specified value: 20-28 ohms

If specified values are not obtained:
- Replace EVAP canister purge regulator valve.

CHECKING BATTERY POSITIVE VOLTAGE (B+) SUPPLY
- Disconnect harness connector on valve.

2-Pin Connector:

- Connect VAG 15278 voltage tester between connector terminal 1 and Ground (GND) using cable from VW 1594 test kit.
- Use On-Board Diagnostics (OBD) output diagnostic test mode (DTM) to activate fuel pump relay.
^ LED must light up

If LED does not light up, perform following tests:
- Check the Heated Oxygen Sensor (HO2S) circuit breaker -S73- (brown holder in electronics box, passenger side footwell)
- Check continuity in wiring from terminal 1 of connector on EVAP canister purge regulator valve to circuit breaker using wiring diagram.
^ Specified reading: maximum 0.5 ohms
- Check fuel pump relay and activation.

CHECKING EVAP CANISTER PURGE REGULATOR VALVE ACTIVATION

- Connect US 1115 LED tester or equivalent to EVAP canister purge regulator valve connector terminals 1 and 2 using adapters from VW 1594 connector test kit.
- Use DTM to activate EVAP canister purge regulator valve.
^ LED must blink

If LED does not blink or lights up continuously:
- Connect VAG 1598 test box to ECM wiring harness using VAG 1598/12 adapter. Refer to Computer and Control Systems, System Diagnosis, VAG 1598 Pin Out Box Connecting. Connecting VAG 1598/31 Test Box
^ ECM is not connected.

If LED lights up continuously:
- Check wiring for short circuit to GND between valve connector terminal 2 to test box socket 12.

If LED does not blink:
- Check wiring for continuity between connector terminal 2 and test box socket 12.
^ Specified reading: maximum 1.0 ohm
- If necessary, eliminate open circuit or short circuit to GND between EVAP canister purge regulator valve connector terminal 2 and ECM connector -D- terminal 1.

If there is no open circuit or short circuit
- replace ECM.