P2B66Coolant Pump D Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2B66 is the open-circuit code for the control line of coolant pump D, the pump a manufacturer labels D in its thermal management. The driver stage in the engine computer detects a broken wire, an unplugged connector or a pump input that no longer draws current. No manufacturer documents this exact code publicly. Ford's 2024 summary shows the analogous logic for pumps A and B (P2600, P261A): a continuous check from 11 V battery voltage, in which the smart driver reports the output fault. Under CARB 13 CCR 1968.2 (e)(15), output components must be watched for circuit faults. A short to ground is P2B67, a short to voltage P2B68; pumps C and E use P26F4 and P2DF4. Without control the pump stays off and its loop loses cooling.
- What you may notice
- Warning lamp with stored code
- Pump D does not respond to commands
- Higher temperature in the loop served by pump D
- Likely causes
- LikelyPump connector loose, corroded or unplugged
- PossibleControl wire broken between engine computer and pump
- RareControl input inside the pump open
- 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: €50 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.