What it means
The ECM detects a high 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 circuit voltage is too high, which can indicate a signal short to battery voltage, an open sensor, or a poor connector contact.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- 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 high reading and note the converter’s operating state.
- Inspect sensor C’s connector and wiring for an open circuit, damaged insulation, corrosion, or a signal wire contacting battery voltage.
- Use the manufacturer’s wiring information to check the signal circuit for an unintended connection to power and verify its connections.
- Test sensor C and the circuit separately as specified to determine whether the sensor is open or the wiring is at fault.
- Repair the fault, clear the code, and confirm the live reading is plausible as the converter operates.
Common fixes
- Reconnect a loose sensor C connector and secure its pins.
- Repair an open or damaged wire in the sensor C circuit.
- Repair wiring shorted to battery voltage or corroded terminals.
- Replace sensor C if testing confirms it is open.
Can I keep driving?
With reduced electric drive, charging limits, or a hybrid/EV warning, avoid long trips and heavy loads until the fault is repaired. Stop safely if power drops significantly or the vehicle 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.