Catalytic Converter: Testing and Inspection
1. Before diagnosing the catalytic converter be certain all other systems are functioning properly (mixture ratio control, ignition system, PCV system and the evaporative emission control system)
2. Remove the catalytic converter from the vehicle. With either opening toward a light source, inspect the ceramic insert from both sides.
If the ceramic insert is broken, melted or clogged the catalytic converter must be replaced.