Test Description

WARNING: This page is about a different car, the 2002 Pontiac Grand Prix, 2002 Chevrolet Malibu, and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers in the diagnostic procedures.

2

If any component DTCs are set, diagnose those DTCs first. A fault in a component can cause the TWC to appear degraded or may have caused the TWC converter failure.

3

Clearing the DTCs allows the catalyst test to be completed up to 6 times this ignition cycle. If the A/C is not turned off the diagnostic will not run. The engine must be warmed up. The TWC needs to be warmed up by raising the engine speed above idle for the specified time prior to each attempted test. Verify if DTC passed or failed this ignition cycle. If the DTC does not pass or fail look for a possible reason that would cause the test to abort.

4

This step includes tests for conditions that can cause the TWC to appear degraded. Repair any problems found before proceeding with this diagnostic procedure.

9

If the TWC needs to be replaced, ensure that another condition which could damage the TWC is not present. Conditions may include misfire, high engine oil or coolant consumption, retarded spark timing, a weak spark, or a rich or lean fuel system. Correct any possible causes of TWC damage before replacing the converter.