Diagnostic Aids

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

Check for the following conditions:

A faulty connection at the PCM, inspect the harness connectors for the following conditions.
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Faulty terminal to wire connections
Inspect the wiring harness for damage.
If the harness appears to be OK, disconnect the PCM, turn the ignition ON and observe a digital multimeter (DMM) connected between the low speed coolfan relay control circuit of the coolfan 1 relay and ground at the PCM harness connector. While moving connectors and the wiring harness related to the coolfan 1 relay, a change in voltage will indicate the location of the fault.

Review the Freeze/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.