Powertrain, generic (extended)

P2D54 Hybrid/EV Battery Pack Coolant Temperature Sensor C Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2D54 flags the signal voltage of battery coolant temperature sensor C as too low. These sensors are NTC thermistors pulled up to a reference, so a falling voltage reads as rising temperature; a short to ground or an internally shorted sensor therefore looks like boiling coolant, while the loop itself may be cold. No manufacturer documents P2D54 publicly. GM uses the same logic for sensor A as P0C44: its battery controller fails the inlet value at 87.9 °C, an ADC count of 133 or less in the 2019 tables and 130 or less in the 2011 Volt, for 1.75 s within 2.5 s, Type B. CARB requires out-of-range checks on battery thermal inputs. Expect warnings and possibly limited power; the high counterpart is P2D55.

Likely causes

Signal wire of sensor C shorted to ground (chafed harness)
Sensor C shorted internally
Moisture or coolant in the connector bridging the pins

Symptoms

  • Live data shows an implausibly hot coolant reading for sensor C
  • Battery cooling runs constantly
  • Warning light and possibly reduced power

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

P2D52P2D55P0C44P0CD7P2E76

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