Powertrain, generic (extended)

P2CF6 Hybrid/EV Battery Pack Coolant Pump B Overspeed/Air in System

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2CF6 reports that battery coolant pump B spins above its commanded speed. Once a centrifugal pump loses its load it accelerates, so the most common explanation is air or a low level in the loop, which the title names directly. Ford shows the pattern on the 2022–2023 F-150 Lightning: under programme 23B09, battery coolant tube assemblies made of the wrong material could leak, and P2B29, the pump A version, could set without any other effect; the remedy was new tubes. Overspeed/dry run (B1) is likewise a separate pump fault category in Ford's 2024 summary. No manufacturer publicly documents P2CF6 for pump B. Bleeding the loop with the prescribed procedure and finding the leak come first; a loose impeller or false speed feedback is rarer. Underspeed is P2CF7, a blocked pump P2CF5.

Likely causes

Air left in the battery loop after service or poor bleeding
Leak at a battery coolant tube or joint lowering the level
Impeller slipping on the shaft or broken
False speed feedback from the pump electronics

Symptoms

  • Gurgling or whining from the pump area
  • Coolant level in the battery reservoir drops
  • MIL or hybrid warning, sometimes without other effect

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–700
Time0.5–3 h

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

Parts involved

hybrid battery coolant pump bbattery pack coolant loop

Related codes

P2CF7P2CF5P2B29P0E1D

References: static.nhtsa.gov, fordservicecontent.com, law.cornell.edu.