Overall Function Test

Start engine and warm to operating temperature. Turn ignition off. Using 2 DVOMs, connect leads by backprobing the connector in the following manner: See Figure.

• DVOM No. 1 positive lead connected to PCM connector terminal No. 46.
• DVOM No. 1 negative lead connected to PCM harness connector terminal No. 43.
• DVOM No. 2 positive lead connected to PCM harness connector terminal No. 52.
• DVOM No. 2 negative lead connected to PCM harness connector terminal No. 106.

DVOM No. 1 is measuring front HO2S voltage and DVOM No. 2 is measuring rear HO2S voltage. Start engine and increase to 2000 RPM and hold steady. Monitor DVOMs and ensure DVOM No. 2 voltage switching frequency (between high and low voltage) is at least 25 percent slower than DVOM No. 1. If operation is not as specified, three way catalyst is not operating properly. If voltage of DVOM No. 1 does not switch (between high and low voltage) at least 5 times within 10 seconds, diagnose fault in front HO2S circuit. See DTC P0130, P0133 OR P0134: FRONT HEATED OXYGEN SENSOR (HO2S) .