Diagnostic Aids

Check the following and repair as necessary:

• Exhaust gas leaks.
• HO2S No. 1 and No. 2 malfunctions.
• Damaged wiring harness.

TWC failure may be caused by the following conditions:

• Engine misfire.
• Retarded ignition timing.
• Inadequate secondary ignition voltage.
• Excessive engine oil or engine coolant consumption.
• Rich engine fueling.