Diagnostic Aids
WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. 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 the engine load. Do not change the engine load, ensure the AC is OFF and the engine cooling fans are not cycling, while a catalyst test is in progress.
- These conditions may cause a catalytic converter to degrade. Inspect for the following conditions:
- An engine misfire
- High engine oil or high coolant consumption
- Retarded spark timing
- A weak or poor spark
- A lean fuel mixture
- A rich fuel mixture
- A damaged oxygen sensor or wiring harness
- If the condition is determined to be intermittent, refer to Intermittent Conditions .
- If an intermittent condition cannot be duplicated, the information included in Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC was set.
- The catalyst may have been temporarily contaminated with a chemical from a fuel additive, fuel contamination or any of the above conditions.