Evaporative Emissions System: Testing and Inspection

Fig. 29 Checking Speed Sensor Cycles:

1. Raise and support vehicle so one rear wheel is off ground.
2. Release parking brake, place shift lever in neutral, and disconnect wiring connector from computer, (located on the LH side of the engine cowl).
3. Connect ohmmeter. Fig. 29
4. Turn rear wheel slowly and ensure ohmmeter needle oscillates consistently.
5. If ohmmeter needle does not deflect, check for proper connection of speed sensor terminals at rear of speedometer.
6. If connection is satisfactory, replace the speedometer assembly.
7. Reconnect wiring connector to computer.

Fig. 24 Connecting Vacuum Gauge:

SPEED SENSOR TO VACUUM SWITCHING VALVE CIRCUIT:

1. Using a 3-way connector, connect vacuum gauge to hose between vacuum switching valve and charcoal canister. Fig. 24
2. Position gauge so it is readable from driver's seat, and run vehicle until it reaches normal operating temperature.
3. Road test vehicle and ensure vacuum gauge indicates zero vacuum below 7 mph, and intake manifold vacuum at speeds above 16 mph.
4. If vacuum is not as described in step 3, test speed sensor and vacuum switching valve.