Canister Purge Control Valve: Testing and Inspection

Valve Locations:

Frequency Valve And On/Off Solenoid Valve:

The frequency valve is located under the intake boot near the mixture control unit. It is a duty cycle solenoid controlled by the Motronic control unit, and is based on engine RPM, load and temperature. It works in conjunction with the on-off solenoid to control the flow of fuel vapors from the charcoal canister to the intake manifold.

Component Location:

TESTING
1. Disconnect the gray harness connector from the valve.

Fig. 42 Evaporative Emissions Control (EEC) System Frequency Valve, 16V:

2. Remove the vacuum hoses from the valve and blow through it.
Air should pass through valve.
3. Apply system voltage to the valve connectors and blow through it. Air should not pass through valve.
4. If the valve fails either test it should be replaced.