C-3 ~ Evaporative Emission Canister (EVAP)

Canister Purge Control Solenoid Circuit Diagram:

C-3 Canister Purge Control Solenoid Diagnostic Chart:

CIRCUIT DESCRIPTION:
Canister purge is controlled by a solenoid that allows manifold and/or ported vacuum to purge the caniater. The ECM provides a ground to energize the solenoid (purge "ON").
The ECM provides voltage to the solenoid under the following conditions:
- ALDL is ungrounded
- Coolant temperature above 60° C
- 20 seconds after engine start
- Vehicle spped over 20 mph
The voltage opens the solenoid for a certain amount of time, allowing a measured amount of ported vacuum to purge the canister. Also, the solenoid is energized when the diagnostic connecter is grounded and the key is ON, engine OFF.



TEST DESCRIPTION:
Numbers below refer to the circled numbers on the diagnostic chart.

1. Checks to see if solenoid is open or closed. The solenoid is normally not energized, so it should be closed.
2. Checks to determin if solenoid was open due to an electrical short or a defective solenoid
3. Completes functional check by grounding test terminal. This should normally energize solenoid, allowing purge.

DIAGNOSTIC AIDS
Make a visual check of vacuum hoses. Check for possible plugged or damaged vacuum fitting(s). Check for possible mechanical fault.