Flow of Diagnosis

1. Verify the customer's original concern by operating the engine to duplicate the condition.
2. Inspect to determine if any of the following mechanical concerns apply:

NOTE: In the event of a three-way catalytic converter failure, always check the muffler to be sure converter debris has not entered muffler.

Mechanical
- Noises and fumes
- Burnout holes
- Loose or corroded clamps or muffler pipe brackets
- Damaged exhaust shield
- Corroded exhaust system flex tube, three way catalytic converter, muffler.
- Grayish, white or black exhaust soot on underbody
- Loose or rusted flange connections.

3. On small leaks, have an assistant hold rags over the tail pipe outlet while listening for the leak. This helps magnify the leak.
4. Using a rubber mallet, tap on the exhaust components to simulate the bouncing action of the exhaust while watching for exhaust-to-body/chassis contact.
5. Lightly tap on the muffler, three way catalytic converter and dual converter Y pipe to determine if there are loose or broken baffles in the muffler or a loose or broken element in the muffler and three way catalytic converter.
6. If the inspection reveals obvious concern(s) that can be readily identified, service as required.
7. If the concern(s) remains after the inspection, determine the symptoms and go to the Symptom Chart. Symptom Related Diagnostic Procedures