Diagnostic Aids
WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The catalyst test may abort due to a change in engine load. Do not change engine load, that is, do not reset A/C, coolant fan, or heater motor while a catalyst test is in progress.
Certain conditions may cause a catalytic converter to degrade. These conditions may include the following conditions:
- Engine misfire.
- High engine oil or high coolant consumption.
- Retarded spark timing.
- Weak spark.
- Lean fuel system.