Circuit/System Testing

WARNING: This page is about a different car, the 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 .
- 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.