Powertrain, generic · Hybrid propulsion

P0C73 Motor Electronics Coolant Pump A Control Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0C73 reports that coolant pump A of the motor electronics, the loop that cools the inverter and often the drive motor, does not run the way the controller commands. Kia's bulletins for Niro and Carnival hybrids use exactly this name. The 2018 Outlander PHEV sets it when, with at least 30 % pump command for over 2 s, pump speed stays between 100 and 1,000 rpm or exceeds 5,300 rpm for 0.5 s; Mitsubishi lists air in the loop, wrong coolant level or mix and frozen coolant first. Toyota tied P0C73 on the 2014-2016 Highlander Hybrid to water corroding the inverter pump connector, Kia to water entering the pump can, Mercedes (M264) to trapped air. Battery pack pump faults use P0C47-P0C4D. Power is reduced to protect the inverter.

Likely causes

Air trapped in the inverter cooling loop, often after coolant service
Water ingress and corrosion at the pump connector or inside the pump housing
Low coolant level, wrong mixture or frozen coolant
Electric pump worn or seized
Control-unit software with faulty judgement logic

Symptoms

  • Malfunction indicator lamp or hybrid warning lamp
  • Coolant warning in the instrument cluster
  • Reduced electric drive power at high load

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

motor electronics coolant pump acoolant circuitwiring harnesshybrid control module

Related codes

P0C74P2BD7P2600P2601P0C4A

References: static.nhtsa.gov, mitsubishitechinfo.com, static.nhtsa.gov, static.nhtsa.gov.