XB158 - Check Left O2S Circuit For Intermittent Short to Power

NOTE: Due to the internal circuitry of the Powertrain Control Module (PCM), an intermittent left Heated Oxygen Sensor (HO2S) signal short to power could produce Continuous Memory Diagnostic Trouble Codes (DTC) 524, 542 or 543.

- Key "OFF".

- Install breakout box, if applicable.

- Breakout box installed, PCM disconnected.

- Connect a test lamp between test pin 43 (HO2S-L) and test pin 40 at the breakout box.

- Key "ON".

- Observe test lamp for an indication of a fault while performing the following (the light will turn on bright if a fault is detected):

- Shake, wiggle, bend the left HO2S circuit from the HO2S to the PCM.

- Lightly tap on the HO2S (to simulate road shock).

- Is a fault indicated?

Yes -- Isolate fault and service as necessary. Remove breakout box. Reconnect all components. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)

No -- Unable to isolate fault at this time. Remove breakout box. Reconnect all components. For further diagnosis using the EEC-IV Monitor Box or Scan Tool, go to Normal Scan Data Values. For further diagnosis of this, or any other symptom, return to Diagnostic Routines. Symptom Related Diagnostic Procedures