H54 - Check HO2S Circuit Wiring Harness For Short to Ground

- Key Off.

- Breakout box installed, PCM disconnected.

- HO2S disconnected.

- Measure resistance between the HO2S Signal Test Pin and Test Pins 24, 51, 76, 77 and 103 at the breakout box.

- Is each resistance greater than 10,000 ohms?

YES -- Go to H55. H55 - Check HO2S For Short to Ground

NO -- SERVICE short circuit. REMOVE breakout box. RECONNECT PCM and HO2S. DRIVE 5 miles/55 mph. Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes