Canister Purge Solenoid: Testing and Inspection

OPERATION
The EVAP solenoid receives 12 volts from the 10 amp number "D1" fuse on the underhood relay panel through CKT 750. The PCM energizes the EVAP solenoid by grounding pin "3E12" (CKT 428). When the solenoid is energized it allows the canister to purge.

The canister is commanded to purge when:

^ Maximum of 150 seconds after closed loop is enabled (time varies depending on coolant temperature at key "ON").

^ Coolant temperature is above 80°C.

^ When the PCM is not enabling injector shut-off for Traction Control and Acceleration reduction.

^ Throttle switch is open.

^ Vehicle speed is above 20 mph.

^ Engine speed is greater than 1100 rpm.

^ Engine metal "over temp" coolant condition is not present.


PROCEDURE
1. Attach hose to vapor line that comes from canister to solenoid and attempt to blow into it. Air should not pass into solenoid. If air passes through solenoid, then replace solenoid.

2. With engine "OFF", go into EVAP solenoid override (PO01). Override of solenoid should cause solenoid to vibrate. Physically touch solenoid (mounted in engine compartment) in override condition. If solenoid is not vibrating, then replace solenoid.

3. With the solenoid vibrating, attach hose to vapor line that comes from canister to solenoid and attempt to blow into it. There should be a noticeable difference in resistance from step 1.