Evaporative Emissions System: Testing and Inspection

INSPECTION

EVAP Control Diaphragm Valve And #3 Hose:

EVAP Control Solenoid Valve Connector Terminal Identification.:

1. Disconnect #3 vacuum hose from the Evaporative Emissions (EVAP) Control System Purge Control Diaphragm Valve (on top of the EVAP Canister). Connect a vacuum gauge to the hose.
2. With engine temperature below 70° C (158° F) start engine and allow it to idle. There should be no vacuum. If vacuum exists:
^ Disconnect the two pin connector from the EVAP Purge Control Solenoid Valve.
^ Measure voltage between BLACK/YELLOW (+) terminal and the RED/GREEN (-) terminal. If there is battery voltage, replace EVAP Purge Control Solenoid Valve and retest.
3. Warm engine up to operating temperature (the cooling fan comes on).
4. Measure vacuum at #3 vacuum hose at the EVAP Purge Control Diaphragm Valve. Vacuum should read manifold vacuum. If no vacuum exists:
^ Disconnect the two pin connector at the EVAP Purge Control Solenoid Valve.
^ Measure vacuum at #3 vacuum hose at the EVAP Purge Control Diaphragm Valve. Vacuum should read manifold vacuum.
^ If no vacuum exists replace EVAP Purge Control Solenoid Valve and retest.
5. Reconnect #3 hose at EVAP Purge Control Diaphragm Valve (on top of the EVAP Canister). Remove fuel cap.

EVAP Control Canister Hose Identification.:

6. Connect a vacuum gauge to EVAP Purge Control Canister Purge Air Hose. Start engine and raise speed to 3500 rpm. Vacuum should appear at gauge after approx. one minute. If no vacuum appears:
^ Connect a vacuum gauge to EVAP Purge Hose and run engine at 3500 rpm.
^ If vacuum appears on gauge, replace EVAP Purge Control Canister.