Powertrain, generic (extended)

P2E82 Cold Start Engine Coolant Pump Overspeed

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2E82 flags an electric main coolant pump that spins faster than requested while the cold-start warm-up strategy runs. GM's 2025 ECM tables (25OBDG03B) subtract reported from requested speed, filter the result and fail the test when it falls below −200 rpm in 8 of 10 seconds; Type B, MIL after two trips. Required: low-flow coolant mode, catalyst warm-up active, a request that changes by less than 50 rpm per sample for 3 s, and inlet coolant at −40 °C or warmer. Outside cold start GM uses P26CE with a speed-dependent limit of −200 to −800 rpm. A pump that turns too freely often moves air instead of coolant, so low coolant or trapped air are the first suspects. A GM patent compares pump speed and current with targets to find such faults.

Likely causes

Low coolant level or air trapped after service, so the impeller runs dry
Impeller loose or damaged, so the motor turns without load
Faulty pump electronics or speed feedback signal
Flow path blocked by a stuck valve, changing the pump load

Symptoms

  • Check engine light after two trips
  • Gurgling noises or weak heater output
  • Rising engine temperature if coolant is missing

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–1,200
Time0.5–3 h

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

Parts involved

engine coolant pump

Related codes

P26CEP2DE9P2B85P2C37P2E81

References: gsi.ext.gm.com, law.cornell.edu, image-ppubs.uspto.gov.