Vehicle Speed Sensor: Testing and Inspection

1. Using a 3-way connector, connect vacuum gauge to hose between vacuum switching valve and charcoal canister.
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 m.p.h., and intake manifold vacuum at speeds above 16 m.p.h..
4. If vacuum is not as described in step 3, test speed sensor and vacuum switching valve.