Component Diagnostic Charts - Port Fuel Injection

Fig. 007 - WIRING DIAGRAM for Chart C-3 Canister Purge Valve. VIN 3, VIN 9, VIN L:

CHART C-3

CANISTER PURGE CHECK

3.0L "N" SERIES, 3.8L "A" & "C" SERIES, 3.8L TURBO "E" & "G" SERIES

FUEL INJECTION (PORT)

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).
If the diagnostic test terminal is grounded with the engine stopped or the following is met with the engine running the purge solenoid is de-energized (purge on).
a. Engine run time after start more than 1 minute.
b. Coolant temperature above 80°C (176°F).
c. Vehicle speed above 5 MPH (8 km/h).
d. Throttle off idle. TPS signal about .75 volt.

Fig. 006 - Chart C-3 Canister Purge Valve.:

1. Checks to see if the solenoid is opened or closed. The solenoid is normally de-energized in this step, so it should be closed.
2. Completes functional check by grounding test terminal. This should normally energize the solenoid and allow the vacuum to drop (purge on).
3. Checks for open or grounded solenoid circuit.
4. Checks to see if ECM control circuit or solenoid is at fault.

Solenoid coil resistance must measure more than 20 ohms. Less resistance will cause early failure of the ECM. Using an ohmmeter, check the purge solenoid, coolant fan relay, or wastegate solenoid (E and G Series only) resistance before installing a replacement ECM, because they could cause failure of the purge circuit.