What it means
The ECM detects a low fault on the dc/dc converter 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
The DC/DC converter lowers high-voltage battery power for the vehicle’s low-voltage electrical system. The ECM monitors temperature sensor C’s signal and sets this code when the circuit voltage is too low, which can result from a signal short to ground, an internally shorted sensor, or a poor connector contact.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- Connector pins corroded - high contact resistance
Symptoms
- Hybrid or EV system warning light
- Reduced power or limited electric drive
- Charging may be limited
- Reduced electric range
How to diagnose it
- Record freeze-frame data and check live data for sensor C to confirm the low reading and note whether converter operation was affected.
- Inspect sensor C’s connector and wiring for corrosion, damaged insulation, a signal wire touching ground, or backed-out pins.
- Check the signal and ground connections for shorts or excessive resistance using the manufacturer’s wiring information.
- Disconnect and test sensor C and its circuit as specified to distinguish an internal sensor short from a wiring fault.
- Repair the identified fault, clear the code, and confirm sensor C’s reading responds plausibly during operation.
Common fixes
- Clean or repair corroded sensor C connector terminals.
- Repair a signal wire shorted to ground or damaged wiring.
- Restore a sound ground or connector contact.
- Replace sensor C if it is internally shorted.
Can I keep driving?
If the warning is accompanied by limited electric drive, reduced power, or charging limits, keep trips short and avoid high loads. Stop somewhere safe if the vehicle loses power or displays a stop-driving warning.
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.