OBD-II code · Powertrain (generic)
P0CA4 Hybrid/EV Battery Charging Voltage High
The HV battery charging voltage exceeds the safe upper limit. Risk of cell damage from overvoltage. Cell-group voltage monitoring is the foundation of HV battery safety — drift here triggers contactor opening, charge inhibit, and reduced power to protect the pack.
Is it safe to drive with P0CA4?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyCharger regulation off
- PossibleBMS disagrees with charger setpoint
- Less likelyPack cell imbalance approaching service threshold
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 3–14 h
- Emissions test
- Usually unaffected
- Parts involved
- Hv Battery, Bms
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.