Flow of Diagnosis

1. Verify the customer concern by road testing the vehicle.
2. Visually inspect the components of the exhaust system and related controls that may affect exhaust gas quality or cause loss of power.





3. Visually inspect for obvious signs of mechanical and electrical damage.
4. Check the exhaust hanger insulators for signs of damage. Shake the entire exhaust system. Make sure the exhaust system is not grounding against the frame or other component.
5. Exercise the wiring and connectors of the components for obvious concerns due to looseness, corrosion, or other damage. This must be done while the engine is fully warmed and the system controls are activated.
6. Check the vacuum lines and connectors for looseness, pinching, leakage, splitting, blockage, or other damage.
7. If a vacuum line or orifice (restrictor) blockage is suspected, correct the cause before proceeding to the next step.
8. If the concern is not visually evident, determine the symptom and proceed to the Symptom Chart.Symptom Related Diagnostic Procedures