P2B29Hybrid/EV Battery Pack Coolant Pump A Overspeed - Dry Run
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- A centrifugal pump that suddenly spins faster while drawing less current has lost its liquid: it is churning air. P2B29 reports exactly this for battery coolant pump A. Porsche describes the detection for the 2018 Panamera 4 E-Hybrid, where the pump watches its speed and current draw against the commanded speed and reports a dry run to the battery controller, but files it as P0C4A00 and notes it may take hundreds of miles to appear. Ford uses P2B29 itself: bulletins 20-2221 (2020 Escape HEV built up to 10 June 2020, stored in the BECM), 20-2293 and 20-2345 (hybrid Explorer, Aviator and Police Interceptor Utility) list it among MIL codes cured by reprogramming. Outside such software cases, look for leaks, low level or poor bleeding. P2B28 is the general performance code.
- What you may notice
- MIL or hybrid system warning
- Pump audibly gurgling or whining
- Battery power or charging limited
- Likely causes
- LikelyAir in the battery coolant loop after service or incomplete bleeding
- PossibleLeak in a battery cooling line lowering the level
- PossibleBattery controller software misjudging pump feedback (Ford 2020 hybrids)
- 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.