P2D54Hybrid/EV Battery Pack Coolant Temperature Sensor C Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- Live data shows an implausibly hot coolant reading for sensor C
- Battery cooling runs constantly
- Warning light and possibly reduced power
- Likely causes
- LikelySignal wire of sensor C shorted to ground (chafed harness)
- PossibleSensor C shorted internally
- RareMoisture or coolant in the connector bridging the pins
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.