Powertrain, generic · Hybrid propulsion

P0C44 Hybrid/EV Battery Pack Coolant Temperature Sensor A Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0C44 reports that the voltage of battery coolant temperature sensor A is too low. The sensor is an NTC thermistor, so a low voltage translates into a very hot reading, and a short to ground or a shorted element is the classic cause. GM documents the code in the battery energy control module: the 2011 Chevrolet Volt sets it when the inlet coolant value reaches 87.9 °C (ADC count 130 or less), the 2019 hybrid tables use the same temperature at an ADC count of 133 or less. The fault must be present for 1.75 s within a 2.5 s window; as a Type B code it turns on the MIL after the second trip. Because the controller can no longer trust the coolant value, it may limit battery power. P0C45 is the high counterpart, P0C42 the generic circuit code.

Likely causes

Sensor signal wire chafed through and shorted to ground
Internally shorted coolant temperature sensor
Coolant or water in the connector bridging the pins

Symptoms

  • MIL and hybrid or EV system message
  • Coolant temperature shown implausibly high in live data
  • Limited charging or drive power

Repair estimate

DifficultyHardWorkshop job
Parts and labour€60–400
Time0.5–2.5 h

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

Parts involved

hv battery pack coolant temp sensor awiring harnessbms

Related codes

P0C42P0C43P0C45P0C46P0CD7

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