Oxygen Sensor

NOTE: Enter this test only when a Code 15 (lean) or Code 17 (rich) is displayed during QUICK TESTS procedure.

O2S CIRCUIT PIN IDENTIFICATION

Circuit	PCM Pin	BOB Pin	Wire Color
O2S	2D	29	BLK

1) Warm engine to operating temperature, and let idle. Unplug O2S. Measure voltage between O2S connector (sensor side) and ground. With engine at idle, voltage should fluctuate between 0.2-0.8 volt.

2) Increase and decrease engine speed while reading voltmeter. When engine speed is decreasing, voltage should decrease. When engine speed is increasing, voltage should increase. If voltage is within specification, go to next step. If voltage is not within specification, replace O2S.

3) With ignition off, install BOB. Leave PCM disconnected. Unplug O2S connector. Measure continuity between O2S test pin and O2S connector wire. If continuity exists, O2S circuit is okay. Return to QUICK TESTS if sent here from there. If not sent here from QUICK TESTS, replace PCM. If voltage is not as specified, repair VMREF wire to VAF. If continuity does not exist, service PCM sensor wire to PCM.