Pre-Diagnostic Troubleshooting Procedure

Do not perform repairs not related to the customer complaint. 

• With the scan tool, read DTCs and record on the repair order  .
• With the scan tool, run a Vehicle Scan Report and a ECU Configuration Report  and save the files for future use.
• Check the vehicle repair history  for any recent repairs that may be related to the customer complaint.
• If possibly related to the customer complaint, verify the vehicle build configuration  with the OEM Vehicle Build Configuration on Service Library. Properly configure the vehicle if necessary.
• If possibly related to the customer complaint, verify all Electronic Control Units (ECU)s have the same Original Vehicle Identification Number (VIN)  . If a mismatch is found, this could indicate the source of the problem. Typically, this condition will cause multiple communication DTCs to set however, this is not always the case.
• With a scan tool, check all ECU's for available software updates  that are related to the customer complaint.
  • Read Service Bulletins to determine if the software update is applicable to the customer complaint.
    • Update the (ECU)s if necessary.
• Use the Search function in Service Library to read any related information under SERVICE ACTIONS/TIPS  .
  • Perform any Service Bulletins or other procedures that may apply.

• Check for aftermarket electrical accessories  . Be certain they are installed properly and do not interfere with any related power, ground, signal, or communication circuits. Be certain aftermarket wiring harnesses are routed away from vehicle wiring harness to avoid electromagnetic interference (EMI) where applicable.