P0C7C
Hybrid/EV Battery Temperature Sensor G Circuit.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- C
- AreaHybrid propulsion
- 7C
- FaultThe specific fault in that area
What it means
P0C7C is a generic code meaning the hybrid or EV battery control unit has found a fault in the circuit for battery temperature sensor 'G'. The control unit saw a signal outside the expected range, such as a reading that was too high or too low, or one that was implausible compared with other sensors. The battery relies on accurate temperature data to manage charging, discharging and cooling. Which part of the pack sensor G monitors depends on the model.
Symptoms
- Hybrid or EV system warning light on the dashboard
- Reduced power or limited acceleration
- Reduced regenerative braking or charging
- Battery cooling fan running constantly or at an unusual speed
- Reduced electric-only range or the engine running more often on a hybrid
- Car going into limp mode or refusing to enter Ready mode
Possible causes
- Faulty battery temperature sensor Glikely
- Damaged, chafed or corroded wiring to the sensor, including open circuit or short to earth or voltagelikely
- Poor connection or corroded terminals at the sensor or battery monitoring connectorpossible
- Fault in the battery monitoring or control modulepossible
- Moisture or coolant ingress in the battery pack harness or connectorpossible
- Outdated or faulty control unit software, where the manufacturer has identified this as a known cause for the modelrare
How to diagnose
- Read all stored and pending codes and note any other battery temperature or voltage codes, as related faults point towards a shared wiring or module problem.
- Read the freeze frame data and the live temperature values for all battery sensors, comparing sensor G with the others and with ambient temperature on a cold car.
- Check for relevant technical service bulletins and software updates for the model and engine.
- Visually inspect the accessible wiring and connectors for chafing, damage, corrosion, moisture and loose terminals.
- Follow the manufacturer's high-voltage safety procedure before touching any high-voltage components, and only proceed if you are trained and qualified to do so.
- With the circuit isolated, measure the sensor resistance and compare it with the manufacturer's specification at a known temperature.
- Test the sensor wiring for continuity, short to earth and short to voltage between the sensor and the control module.
- If the sensor and wiring are good, check the battery monitoring module's supply, earth and communication, and confirm the fault is in the module before replacing it.
How to fix
- Replace the faulty battery temperature sensor or sensor assembly as specified for the model.
- Repair or replace damaged wiring, and clean or replace corroded or loose connectors.
- Dry out and properly seal any connector affected by moisture, and trace and fix the source of ingress.
- Replace or reprogram the battery monitoring module if testing confirms it is at fault.
- Install the latest manufacturer software update if it addresses this fault.
- Clear the codes after repair and confirm the fault does not return on a road test.
Can I keep driving?
The car may be driveable, but power is often limited and the battery is not being protected as well as it should be, so get it checked soon. Stop driving if the car loses power, shows a red warning, or you notice a burning smell, heat or smoke from the battery area.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.