Where to Start
If you are reasonably certain that the problem is engine related, the first place to start is with the Powertrain On-Board Diagnostic (OBD) System Check. Testing and InspectionIMPORTANT: Do Not clear the DTCs unless a diagnostic procedure instructs you to do so.
While performing a diagnostic procedure, you may need to gain access to certain components. Be sure to read the Service and Repair procedures for those components.
During the diagnosis or if a wiring problem is present, refer to Diagrams. The Electrical Diagrams contain complete information on vehicle wiring and includes the following information:
^ The wiring schematics. including the circuit numbers and the colors.
^ The electrical component, the connector, the splice, and the ground locations.
^ The wiring repair procedures.
^ The wiring repair parts information.
^ How to check for and repair a poor terminal contact.