Initial Inspection and Diagnostic Overview

1. Verify the customer concern by running the engine at 2000 rpm or by road testing the vehicle.
2. Visually inspect the components of the exhaust system and the related controls that may affect exhaust gas quality or cause a loss of power.

Visual Inspection Chart:

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