P2B65Coolant Pump B Overspeed/Air in System
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- When a coolant pump draws in air, its impeller loses load: speed climbs and current drops. P2B65 reports this for coolant pump B. Ford's 2024 gasoline OBD summary lists it as failure type B1 (overspeed/dry run) of pump B under P261A. Bentley stores P2B6500, labelled air in system and static, in both engine control units 0001 and 0011 of the W12 Continental GT, GTC and Flying Spur from model years 2018 to 2024, often together with P2B8600 for pump A and a coolant warning in the instrument panel. Bentley's bulletin 2066669 (revisions 1 to 4, latest November 2025) starts with a pressure test and then checks vent hose 975 122 447H, whose built-in check valve can restrict flow; after replacement the circuit is bled. Pump D has P2B6C.
- What you may notice
- Coolant or overheating warning in the instrument cluster
- Falling coolant level in the expansion tank
- Gurgling noise or fluctuating temperature display
- Likely causes
- LikelyAir left in the circuit after filling or repair
- LikelyCoolant loss through a leak, level too low
- PossibleRestricting check valve in the vent hose (Bentley W12, 975 122 447H)
- RareSpeed or current detection inside the pump faulty
- 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 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.