H19 - Check HO2S For Short to Ground

- Key "OFF".

- Breakout box installed, Powertrain Control Module (PCM) disconnected.

- Heated Oxygen Sensor (HO2S) disconnected.

- Measure resistance between PWR GND and HO2S circuit at the HO2S connector.

- Measure resistance between HO2S circuit and HO2S GND and/or SIG RTN at the HO2S connector. H - Test Schematic

- Is resistance greater than 10,000 ohms?

Yes -- For Diagnostic Trouble Codes (DTC): 139, 144, 171, 174, 175 or 178, go to H90. H90 - Check Continuous Monitor Diagnostic Test Mode

For other DTCs:: Remove breakout box. Reconnect HO2S. Replace PCM. Drive vehicle 5 miles/55 mph. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)

No -- Replace HO2S. Remove breakout box. Reconnect PCM. Drive vehicle 5 miles/55 mph. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)