Powertrain, generic (extended)

P2D55 Hybrid/EV Battery Pack Coolant Temperature Sensor C Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2D55 is the counterpart to P2D54: the signal of battery coolant temperature sensor C sits at or near the reference voltage. On an NTC circuit with pull-up that is what an open circuit produces, so the controller sees an impossibly cold coolant value. Typical findings are a connector not plugged back after battery work, a broken wire, a spread terminal, or a short to a supply line; an open sensor element is less common. No manufacturer documents P2D55 publicly. GM's sensor A equivalent P0C45 fails below -40 °C, at an ADC count above 3890 (2019) or 3823 (2011 Volt); either must persist for 1.75 of 2.5 s, Type B. CARB demands such out-of-range checks. Battery heating may not work properly in winter.

Likely causes

Open circuit: connector unplugged, broken wire or spread terminal
Signal wire shorted to a supply voltage
Open sensor element

Symptoms

  • Live data shows about -40 °C for sensor C
  • Battery heating or cooling uses substitute values
  • Warning light; reduced power in cold weather possible

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–700
Time0.5–4 h

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

Parts involved

hv battery pack coolant temp sensor cwiring harnessbms

Related codes

P2D52P2D54P0C45P0CD8P2E77

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