Powertrain, generic (extended)

P2B29 Hybrid/EV Battery Pack Coolant Pump A Overspeed - Dry Run

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

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.

Likely causes

Air in the battery coolant loop after service or incomplete bleeding
Leak in a battery cooling line lowering the level
Battery controller software misjudging pump feedback (Ford 2020 hybrids)

Symptoms

  • MIL or hybrid system warning
  • Pump audibly gurgling or whining
  • Battery power or charging limited

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–700
Time0.3–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hybrid battery coolant pump abattery pack coolant loop

Related codes

P2B28P0CFFP0C4AP0E3BP2B2A

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.