O2S3 - Check O2S Circuit For Shorts

- Key OFF.

- Install Breakout Box (leave PCM disconnected).

- Disconnect the O2S connector.

- Measure the resistance between BOB Test Pin O2S and ground (should read greater than 10,000 ohms).

- Key ON.

- Measure the voltage on BOB Test Pin O2S (should be 0 Volts).

- Are the measurements correct?

Yes -- Replace the O2S.

No -- Service the O2S wire to the PCM.