Powertrain, generic (extended)

P2C72 Hybrid/EV Electronics Cooling System Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2C72 says the coolant loop serving the hybrid or EV power electronics (inverter, DC/DC converter, often the charger) does not cool as expected. CARB requires a functional check of inverter cooling performance where feasible, on top of the circuit checks of pump and sensors. No manufacturer documents P2C72 publicly. The closest documented code is P0A93: Hyundai traced it on the 2011 Sonata Hybrid to the electric water pump, with a hybrid warning, no EV mode and weak acceleration (bulletin 14-HC-001). A Hyundai patent shows one way to judge the loop: with the car at rest a fixed pump output is applied, and an impeller turning faster than the reference reveals low coolant. Leaks, air, a weak pump, a clogged radiator or a failed fan are typical. Power is limited to protect the electronics.

Likely causes

Low coolant level or leak in the electronics loop
Air trapped in the loop after service
Electronics coolant pump delivering too little flow
Clogged low-temperature radiator or failed cooling fan

Symptoms

  • Hybrid system warning and MIL
  • Reduced power, no EV mode, especially in heat or under load
  • Inverter over-temperature codes stored as well

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,200
Time0.5–4 h

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

Parts involved

hybrid electronics coolant pump ahybrid electronics radiatorpower electronics coolant loop

Related codes

P0A93P0C31P2C66P2C67P2C68P0A3C

References: law.cornell.edu, static.nhtsa.gov, patents.google.com.