P0AA4 Hybrid Battery Pack Temperature Sensor B Circuit Intermittent

P0AA4 indicates an intermittent hybrid battery pack temperature sensor B circuit fault. Sensor B data becomes invalid only under certain conditions.

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 clear intermittent sensor B faults without checking connector retention and harness movement.

Useful checks before replacing parts

Review freeze-frame load, cooling fan operation, road vibration, moisture exposure, temperature history, and related intermittent temperature codes.
Inspect sensor B connector pin fit, harness flex points, water intrusion, loose grounds, battery ECU terminals, and airflow duct movement.
Wiggle-test low-voltage sensor wiring while graphing sensor B and nearby temperature sensors to reproduce spikes or dropouts.

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.