P0C72
Hybrid/EV Battery Temperature Sensor E/F Correlation.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- C
- AreaHybrid propulsion
- 72
- FaultThe specific fault in that area
What it means
P0C72 is a generic hybrid/EV code meaning the battery control unit sees a correlation fault between traction battery temperature sensors E and F. The two readings disagree by more than expected for their positions, or one does not track the other as the pack heats and cools. The control unit can no longer trust the pack temperature data, so it may limit power or charging to protect the battery.
Symptoms
- Hybrid or EV system warning light on the dashboard, often with the malfunction indicator lamp
- Reduced power or limp-mode behaviour
- Reduced or restricted charging and regeneration
- Battery cooling fan running louder or more often than normal
- Reduced electric range or the engine running more often on a hybrid
- Poor or uneven state-of-charge readings
Possible causes
- Faulty or drifting battery temperature sensor E or Flikely
- Damaged wiring, corrosion or a loose connector in the sensor circuitlikely
- Uneven pack temperature from a blocked cooling duct, failed battery fan or poor coolant flow, depending on the model's cooling designpossible
- Faulty battery monitoring or control module, or its internal sensor input circuitpossible
- Deteriorated cells or modules causing a local hot spot near one sensorpossible
- Outdated or faulty control unit softwarerare
How to diagnose
- Read all stored and pending codes and the freeze frame data, and note any other battery temperature, cooling fan or voltage codes.
- Check the live data for all battery temperature sensors and compare E and F with the others and with ambient temperature after the car has been left to cool.
- Inspect the battery cooling air intake, ducts, filter and fan for blockages, debris or damage.
- Check the sensor wiring and connectors for damage, moisture or corrosion, but only where they can be reached without opening the high-voltage pack.
- Check the cooling fan or coolant pump operation, using the model's test procedure.
- Compare the sensor readings with the manufacturer's expected values, as sensor positions and tolerances vary by model.
- Have a technician trained in high-voltage systems check the sensor resistance and module inputs, following the isolation procedure.
- Check for software updates or technical bulletins for the model.
How to fix
- Repair or replace damaged wiring or connectors in the sensor circuit.
- Replace the faulty temperature sensor or sensor harness, using a qualified high-voltage technician where the pack must be opened.
- Clear any blockage in the battery cooling duct or filter and repair or replace a failed fan or cooling component.
- Repair or replace the battery monitoring module if the sensor input is confirmed faulty.
- Service or replace the affected battery modules if a genuine hot spot or cell fault is found.
- Apply a manufacturer calibration update if one is known to cover this fault.
Can I keep driving?
The car can usually be driven carefully for a short time, but expect reduced power and charging, and have it checked soon. If the temperature warning is displayed, there is a burning smell or the power drops sharply, stop safely and seek assistance.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.