P0C73
Hybrid Battery Pack Cooling Pump Performance
BMS detects insufficient flow from the battery cooling pump despite commanded operation, indicating mechanical degradation or air pocket.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
Common causes
Ordered by how often each turns out to be the cause.
- Pump wornCommon
- Air trapped in cooling circuitPossible
Parts involved
- Battery Cooling Pump
- Coolant Circuit
P0C73 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.