Circuit/System Testing for the DTC

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Observe the DTCs with the scan tool.
- If DTC P0602 is set, attempt to program the ECM before replacing the ECM. Refer to Service Programming System (SPS) .
- 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.