X86 - Check Front/Left HO2S For Short to Power

NOTE: Due to the internal circuitry of the Powertrain Control Module (PCM), a Left/Front Heated Oxygen Sensor (HO2S) signal short to power could produce a Diagnostic Trouble Code (DTC) 542/543.

- Key "OFF".

- Disconnect left or front H02S.

Oxygen Sensor Connector:

- Measure resistance between HO2S signal pin and KEY POWER pin at the HO2S connector.

- Is resistance greater than 10,000 ohms?

Yes -- Go to X87. X87 - Check HO2S Circuit For Short to Power

No -- Replace HO2S. Remove breakout box. Reconnect all components. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)