Without Hard DTCs/Lamp Fault Codes

DIAGNOSING CUSTOMER CONCERNS WITHOUT HARD DIAGNOSTIC TROUBLE CODES

If a lamp fault code (LFC) is reported by the customer but is not present when the vehicle comes in for service, follow the Diagnostic Instructions procedure to identify the intermittent DTC.

Once the DTC is known, read the Normal Operation section of the pinpoint test for the DTC involved.
- Follow the deactivation procedure.
- Determine the location of components involved in creating the DTC.
- Carry out a thorough visual inspection of:
- components.
- connectors.
- splices and wiring harnesses.
- pinched wires.
- worn insulation on conductors.
- opens, shorts or loosely mounted sensors.

Refer to the Possible Causes section of the pinpoint test for the DTC involved, which list the common concerns that relate to the DTC. Concerns are listed according to priority.