Diagnostic Instructions

• DIAGNOSTIC SYSTEM CHECK INSTRUCTIONS  provides an overview of each diagnostic step.
• Continue through the Diagnostic System Check until you are directed to follow a particular diagnostic or repair procedure. Once a repair has been completed, perform the DIAGNOSTIC REPAIR VERIFICATION  and verify the customer concern has been corrected.

The diagnostic procedures within this manual are developed on the assumption that the following areas function as designed:

• The 12V battery is fully charged and cables are clean and tight. Refer to BATTERY INSPECTION/TEST .
• Fuses are not open. Refer to POWER DISTRIBUTION SCHEMATICS and ELECTRICAL CENTER IDENTIFICATION VIEWS .
• Ground circuits for the area of customer concern are clean, tight, and in the correct location. Refer to GROUND DISTRIBUTION SCHEMATICS and HARNESS ROUTING VIEWS .
• All connections/connectors for the area of concern are fully seated. Refer to COMPONENT CONNECTOR END VIEWS
• There are no aftermarket devices that affect the operation of the system. Refer to CHECKING AFTERMARKET ACCESSORIES .
• The scan tool powers up. Refer to SCAN TOOL DOES NOT POWER UP .