Powertrain, generic · Hybrid propulsion

P0A00 Motor Electronics Coolant Temperature Sensor A Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

General circuit fault on temperature sensor A in the separate coolant loop that cools the inverter and other drive electronics of a hybrid or electric vehicle. The module flags it when the sensor signal cannot be used at all, without a more specific low, high or plausibility verdict; those cases have their own codes P0A01 to P0A04. No manufacturer documents P0A00 publicly. GM's Two-Mode hybrid trucks monitor the same sensor only through P0A01 to P0A03, and CARB requires every input of the inverter thermal management to be checked for circuit faults. Without a valid reading the control unit usually limits electric drive power to protect the electronics.

Likely causes

Corroded or loose connector at the sensor in the inverter coolant loop
Temperature sensor element failed
Damaged signal or reference wire between sensor and hybrid control module
Fault in the input stage of the hybrid or inverter control module

Symptoms

  • Hybrid system or check engine warning light
  • Reduced electric drive power
  • Inverter coolant pump or radiator fan running constantly as a precaution

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–900
Time0.5–3 h

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

Parts involved

motor electronics coolant temperature sensorhybrid inverterwiring harness

Related codes

P0A01P0A02P0A03P0A04P2BD8P0A93

References: law.cornell.edu, gsi.ext.gm.com, patents.google.com.