P2D40
Hybrid/EV Battery Cooling System C Performance
The hybrid battery cooling system C does not maintain target temperatures under load. Coolant flow, radiator fouling, or pump output reduced on this branch.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
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.
- Radiator fins fouled - reduced heat rejectionCommon
- Pump output degraded with agePossible
- Pack cell imbalance approaching service thresholdLess likely
Parts involved
- Hybrid Battery Cooling System C
- Battery Pack Coolant Loop
P2D40 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.