Important Preliminary Checks Before Starting 
Perform the 
Diagnostic System Check - Engine Controls 
 before using the symptom tables. Verify that all of the following conditions
are true:
|     •  | The engine control module (ECM) and the malfunction indicator lamp (MIL)
are operating correctly. | 
 
|     •  | There are no diagnostic trouble codes (DTCs) stored. | 
 
|     •  | Verify the customer concern and locate the correct symptom listed below.
Inspect items indicated under that symptom. | 
 
|     •  | Several of the symptom procedures direct the technician to perform a visual/physical
inspection. This important step can lead the technician to the cause of the problem
without further checks and can save valuable time. | 
 
|     •  | Verify the correct installation and operation of electronic options, such
as lights and cellular phones. | 
 
|     •  | Use the following tables when diagnosing a symptom concern: | 
 
|     •  |  If the condition cannot be isolated using the appropriate table, refer
to 
Intermittent Conditions 
 for further diagnosis. |