Powertrain, generic · Hybrid propulsion

P0C45 Hybrid/EV Battery Pack Coolant Temperature Sensor A Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0C45 indicates that the signal of battery coolant temperature sensor A sits near the reference voltage. On an NTC circuit with pull-up this looks like extreme cold and usually comes from an open circuit, an unplugged connector or a short to voltage. GM uses the code in the battery energy control module: the 2011 Chevrolet Volt fails the test below -40 °C at an ADC count above 3823, the 2019 hybrid tables at a count above 3890. In both cases 1.75 s within 2.5 s are needed, and the Type B rating lights the MIL after two trips. With the inlet reading lost, the controller runs the battery cooling and heating on substitute values and may cut power in hot or cold weather. The low counterpart is P0C44; sensor B reports the same fault as P0CD8.

Likely causes

Open signal or ground wire, or connector not latched
Coolant temperature sensor open internally
Signal wire shorted to a voltage source

Symptoms

  • MIL after two trips
  • Coolant temperature shown at about -40 °C in live data
  • Reduced charging power in extreme temperatures

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

P0C42P0C43P0C44P0C46P0CD8

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