P0C4DHybrid/EV Battery Pack Coolant Pump A Supply Voltage Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0C4D is the counterpart to P0C4C: the voltage measured on the supply of battery coolant pump A is higher than the controller allows. That can come from a feed wire shorted to another, more highly loaded circuit, from a relay that stays closed when the pump should be off, or from an overall excessive on-board voltage, for example a faulty DC/DC converter. No manufacturer documents P0C4D publicly. Ford's bulletins for the 2020 Escape, Explorer and Aviator hybrids name the sibling P0C4B for the open supply, and Bentley describes the feed of the same pump with fuse and relay for 2025–2026 hybrids. CARB requires the electrical components of battery thermal management to be monitored. If several modules log overvoltage at once, the 12 V supply is the more likely culprit than the pump circuit.
- What you may notice
- MIL or hybrid or EV warning
- Coolant pump running although the system is switched off
- Likely causes
- PossibleSupply wire shorted to another voltage-carrying circuit
- PossiblePump relay sticking closed
- RareExcessive 12 V system voltage from a faulty DC/DC converter
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €20 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.