Diagnostic Aids

An intermittent may be caused by a rubbed-through wire insulation or a wire contacting the exhaust. Check for the following conditions:

• A poor connection or a damaged harness - Inspect the harness for a short to ground in the sensor signal circuit. Ensure that the HO2S2 pigtail is not contacting the exhaust. Check for the following conditions:
• Improper mating
• Broken locks
• Improperly formed
• Damaged terminals
• Poor terminal-to-wire connection
• Damaged harness
• Intermittent test - Observe HO2S2 on the scan tool while moving the related connections and the wiring harness with the ignition ON. If the failure is induced, the HO2S2 display will change. This may OK, then the ECM connection or ECM is malfunction.