P0AA5 Hybrid/EV Battery Positive Contactor Control Circuit

P0AA5 indicates a hybrid or EV battery positive contactor control circuit problem. The controller cannot command or monitor the positive contactor control path correctly.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System: Hybrid / EV
Scope: iso-sae-controlled-p0
Standard: SAE J2012 / ISO 15031-6
Source: legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not bypass the positive contactor control circuit or force ready mode with this fault present.

Useful checks before replacing parts

Check positive contactor command, control voltage, feedback, 12-volt supply, pack voltage, precharge state, freeze-frame data, and related contactor codes.
Inspect contactor control wiring, battery ECU connectors, fuses, grounds, service disconnect seating, corrosion, water intrusion, and connector locks.
Verify contactor state changes during ready-up and shutdown with service data before replacing battery components.

Related OBD-II codes

These nearby hybrid / ev entries can help compare wording and fault area. They may share the same verification status as the source database.