P0C8C
Hybrid/EV Battery Temperature Sensor I Circuit Intermittent/Erratic.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- C
- AreaHybrid propulsion
- 8C
- FaultThe specific fault in that area
What it means
P0C8C is a generic powertrain code meaning the control unit has detected an intermittent or erratic signal from hybrid/EV battery temperature sensor 'I'. The battery management system saw the sensor reading jump, drop out or change implausibly compared with neighbouring sensors or expected thermal behaviour. Which physical sensor is 'I' depends on the vehicle and battery pack layout, so check the manufacturer data.
Symptoms
- Hybrid or EV system warning light on the dashboard
- Reduced electric assist or reduced power (limp mode)
- Reduced charging speed or charging stopping early
- Cooling fan for the traction battery running louder or more often than normal
- Fault that comes and goes, sometimes clearing when the car is restarted
- Reduced electric-only range or poorer fuel economy on a hybrid
Possible causes
- Loose, corroded or damaged connector at the battery temperature sensor or battery module sensor harnesslikely
- Damaged or chafed wiring in the sensor circuit causing intermittent open or short circuitlikely
- Failing battery temperature sensor giving erratic readingspossible
- Fault within the battery monitoring unit or battery management module sensor inputpossible
- Moisture or contamination in the battery pack connectors or sensor harnesspossible
- Outdated or faulty battery management software, where the manufacturer has identified this as a known issuerare
How to diagnose
- Read all stored and pending codes and note any other battery temperature, voltage or communication faults alongside P0C8C
- Review freeze frame data and check whether the fault occurred during charging, driving, hot or cold conditions
- Check the manufacturer's information to identify which sensor is 'I' and where it is located on that model
- Using live data, compare the suspect sensor reading with the other battery temperature sensors and ambient temperature, watching for sudden jumps or dropouts
- Carefully inspect the accessible sensor connectors and harness for damage, corrosion, moisture or poor pin tension, following high-voltage safety procedures
- With the harness gently moved (wiggle test) watch the live reading for dropouts, only on circuits confirmed as low voltage
- Measure sensor resistance and circuit continuity against manufacturer specifications, with the system safely isolated
- Check for applicable software updates or technical bulletins for the battery management system
How to fix
- Repair or replace damaged wiring in the sensor circuit
- Clean, reseat or replace corroded or loose connectors
- Replace the faulty battery temperature sensor or sensor assembly as the manufacturer specifies
- Replace or repair the battery monitoring or management module if the sensor input is proven faulty
- Dry out and seal any moisture ingress and fix its source
- Update the battery management software if a known fault with an outdated calibration applies
Can I keep driving?
The car can usually be driven short distances, but expect reduced power or limited charging as the system protects the battery. Get it checked soon, and stop driving if a red warning appears, the battery overheats or there are unusual smells.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.