Diagnostic article Generic OBD-II
P0AA2: A close command does not produce the required contactor status
P0AA2 checks failure to close the battery contactor and also recognizes an open service-disconnect status.
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Documented application
2009 General Motors diagnostic parameter file 09OBDG08 Engine Diagnostics.pdf. Section-specific modules and calibrations; no per-code model or engine applicability established.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P0AA2 identifies a battery contactor that has not reached the required closed status in GM's BAS hybrid implementation. The source includes a failure to close after a command and a separate branch for an active open-service-disconnect status.
An open status is not automatically a failed contactor
The table waits at least three seconds after a close command before judging the specified non-defaulted contactor status. It also distinguishes states associated with impact, overtemperature or an engine-controller open command. Those status details matter because the system can remain open for reasons other than a physically defective contactor.
The service-disconnect branch is especially important. A code associated with an open disconnect does not justify forcing the contactor closed or bypassing an interlock. Its cause and the permitted restoration procedure must be established from the exact vehicle information.
Preserve the command and reason for remaining open
Record the close request, elapsed time and detailed contactor status rather than relying only on a generic stuck-open label. The summary does not authorize a contactor replacement from the code alone.
Hybrid isolation and contactor assessment require the prescribed professional procedures. Verification should confirm that the system is legitimately permitted to close, reaches the correct status and completes its monitoring. Clearing P0AA2 or attempting repeated startups does not establish that the condition preventing closure has been resolved.
Source and applicability
2009 General Motors diagnostic parameter file 09OBDG08 Engine Diagnostics.pdf. Section-specific modules and calibrations; no per-code model or engine applicability established. This explanation describes the documented monitor, not a universal repair procedure.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Hybrid/EV Battery Positive Contactor Circuit Stuck Open
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT