Test Description

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

1. 2
   
   If any component DTCs are set, diagnose those DTCs first. A fault in a component can cause the converter to appear degraded or may have caused its failure.
2. 3
   
   Clearing the DTCs allows the catalyst test to be completed up to 18 times and 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 converter needs to be warmed-up by raising the engine speed above idle for the specified time prior to each attempted test. Check and see 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.
3. 4
   
   This step includes tests for conditions that can cause the TWC to appear degraded. Repair any problems found before proceeding with this table.
4. 9
   
   If the three-way converter needs to be replaced, make sure that another condition is not present which could damage the converter. These conditions may include misfire, leaking or plugged fuel injectors, high engine oil or coolant consumption, retarded spark timing or weak spark. Correct any possible causes of converter damage before replacing the converter.