What it means
The HV battery temperature sensor G reports a circuit intermittent/erratic fault. Cell-group temperature monitoring impaired on this channel.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Temperature sensor G measures a cell-group area inside the high-voltage battery, and the battery control system monitors its signal for stable, plausible temperature data. P0C80 sets when the sensor G circuit signal changes erratically or intermittently, often because a connector is loose or vibration disrupts its contact.
Common causes
Most likely first.
- Connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Read freeze-frame data and battery-system codes to see whether sensor G faults coincide with vibration, temperature changes, or other battery warnings.
- Watch live sensor G data alongside nearby temperature channels to identify sudden jumps or dropouts.
- Inspect accessible sensor G connectors and wiring for an incompletely seated plug, damaged insulation, corrosion, or a loose ground reference.
- Have the sensor G circuit checked for intermittent contact using the manufacturer’s procedure and appropriate high-voltage precautions.
- Confirm the sensor reading remains stable under the specified test conditions before replacing the sensor.
Common fixes
- Seat and secure a loose sensor G connector.
- Repair damaged wiring or an unstable ground reference in the sensor G circuit.
- Replace a connector with intermittent contact if repair is not supported.
- Replace sensor G if testing confirms the sensor itself is erratic.
Can I keep driving?
Seek prompt diagnosis if the warning returns or power and charging are restricted, since the fault can recur unexpectedly and cause the system to limit battery use. Avoid opening or disturbing high-voltage battery wiring.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.