Circuit/System Testing for the DTC

WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

Observe the DTCs with the scan tool.
- If DTC P0602 is set, attempt to program the ECM before replacing the ECM. Refer to Control Module References for ECM replacement, setup, and programming.
- If DTC P0602 resets, replace the ECM.
Test the voltage and ground inputs to the ECM for the following:
- A short
- An open
- High resistance

If all circuits test normal, replace the ECM.