What it means
The motor electronics coolant temperature sensor C reports a circuit low condition. Power electronics cooling cannot be regulated reliably.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Motor electronics coolant temperature sensor C sends a signal used to monitor power electronics coolant temperature. P2BDE sets when the control module detects Sensor C’s signal voltage lower than expected, often due to a signal wire short to ground or an internally shorted sensor.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Power electronics or hybrid-system warning
- Reduced power or limited operating mode
How to diagnose it
- Check freeze-frame data and related codes to see when Sensor C’s low-circuit fault occurred and what temperature the module reported.
- Inspect Sensor C’s connector and harness for corrosion, damaged pins, or a signal wire rubbed through and contacting ground.
- Compare Sensor C’s scan-tool reading with other available coolant temperature readings and ambient temperature to check for an implausible value.
- Test the Sensor C signal wire for a short to ground and check its connector terminals using the manufacturer's wiring diagram and specifications.
- If the wiring is sound, test Sensor C for an internal short according to the manufacturer's procedure and replace it if it fails.
Common fixes
- Clean and secure corroded Sensor C connector pins.
- Repair the Sensor C signal wire where it is shorted to ground or damaged.
- Replace Sensor C if it has an internal short or fails the specified test.
Can I keep driving?
Stop safely if a power electronics overheating warning appears or power is reduced; unreliable Sensor C data can impair cooling control and overheating may damage the inverter or motor electronics. If no warning is present, minimize driving and arrange prompt diagnosis.
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.