Chart C3 - Canister Purge Check

Canister purge is controlled by a solenoid that allows manifold vacuum to purge the canister when energized. The ECM supplies a ground to energize the solenoid (purge on). The purge solenoid is energized (purge on) if the ALDL "test" terminal is grounded with the engine stopped or if following conditions are met:

• Engine run time is more than 30-45 seconds.
• Coolant temperature more than 158°F (70°C).
• Vehicle is operating in "closed" loop

1. Checks to see if the solenoid is opened or closed. The solenoid is normally de-energized in this test, so it should be closed.
2. This test completes functional check by grounding "test" terminal. This should normally energize the solenoid and allow the vacuum to drop (purge on).
3. This test checks for open or shorted solenoid circuit.

Fig 1: Chart C3 Schematic, Canister Purge Check (3.3L "A" & "N" Bodies)

Fig 2: Chart C3 Schematic, Canister Purge Check (3.8L "C" & "H" Bodies)

Fig 3: Flow Chart C3, Canister Purge Check