What it means
The ECM detects a range/performance fault on the hybrid/ev battery pack coolant temperature sensor c circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Sensor C measures coolant temperature at a location in the hybrid or EV battery pack. The control module checks whether its signal changes plausibly and agrees with the expected temperature range; this code sets when the reading is out of range or responds abnormally, even if the circuit is electrically connected.
Common causes
Most likely first.
- Sensor characteristic drifted
- Sensor mounting displaced
- Sensor element aged beyond calibration window
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
- Save freeze-frame data, then compare sensor C's live reading with other pack temperature sensors when the vehicle is cold and as it warms.
- Inspect sensor C's mounting and connector for displacement, poor seating, corrosion, or harness damage.
- Check for cooling-system or battery-pack codes that could explain an implausible temperature reading.
- Test sensor C's resistance or signal response over temperature changes using the manufacturer's specification.
- If the sensor response is correct, check the module-side wiring and connections for resistance or signal distortion.
Common fixes
- Secure sensor C in its specified position and reseat its connector.
- Repair damaged or corroded wiring or connector terminals in the sensor C circuit.
- Replace sensor C if its temperature response is outside the manufacturer's specification.
- Address any related battery cooling or pack fault found during diagnosis.
Can I keep driving?
Limit driving if reduced power or charging restrictions appear, and avoid demanding acceleration or charging until the reading is checked. An implausible pack temperature can lead the vehicle to restrict battery use.
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.