P0AA4
Hybrid Battery Negative Contactor Circuit
BMS detects an electrical fault in the negative HV contactor coil circuit.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: shop_only
Common causes
Ordered by how often each turns out to be the cause.
- Contactor coil openCommon
Parts involved
- Hv Contactor Negative
- Bms
P0AA4 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.