P26CDEngine Coolant Pump Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P26CD is set when the control circuit of the engine coolant pump shows a higher voltage than the commanded state allows, for example while the driver is switched off. No manufacturer documents this code in public. CARB's OBD rule asks for output components to be monitored for circuit faults, and the same pump circuit is known from its low-side partner P26CC, which Honda documents on its hybrids in bulletin 25-020. Typical high faults are a control wire touching battery voltage, a relay whose contacts weld shut so the pump keeps running, or an open ground on the pump side. Depending on design the pump then runs permanently or cannot be regulated; the engine module usually stores the code at once and lights the MIL, while warm-up may take longer.
- What you may notice
- Check engine lamp on
- Pump running after the engine is switched off
- Longer warm-up phase
- Likely causes
- LikelyPump control wire shorted to battery voltage
- PossiblePump relay contacts stuck closed
- RareOpen ground at the pump pulling the circuit high
- 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 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.