Every technician knows that water in the PCM is not a good thing. So you replace it and you still have issues, what do you do? SureTrack community member juniur had a Chevrolet Aveo that had water in the PCM and a code P2138. They posed the question to the community, and with the help of fellow community member DAG1365 and others, they were able to resolve the issue quickly.
The following Community Fix summarizes the interaction between members of the community that led to the solution.
2011 Chevrolet Aveo LT 1.6L
Reduced power mode, replaced PCM and dried out connector.
Customer complains that check engine light is on and vehicle has no power.
Diagnostic Steps Performed/Parts Replaced
Confirmed customer’s complaint. Vehicle is in reduced power mode. Found DTC P2138, Accelerator Pedal Position (APP) 1-2 Correlation.
Performed circuit test and found 5v on APP2 signal wire (circuit shorted to voltage). Inspected PCM end of harness found water in the PCM. Replaced PCM, flashed PCM. Still have same issue and same code. Clipped APP2 signal wire at the PCM I have 1.9v leaving PCM. This circuit should have 0v because it receives input from APP2. APP1 circuit has 0v as it is supposed to, checked that just for reference. Is it possible that another wire to the PCM is shorted and back feeding voltage onto this circuit? if so how would I find it?
Best Answer from Community Member DAG1365
It is possible that APP is shorted but check connectors under dash and left kick panel to make sure no other connectors have bad connections. At one time GM had problems with connectors in kick panel getting water in them and corroding.
The PCM connector was saturated with water causing voltage to stray to other circuits. Used electronic cleaning spray and compressed air to dry the connector and all is good. Have no idea how the water got into the PCM and the connector
Replaced PCM and cleaned PCM connector. Vehicle back to full power and code did not return.
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