What it means
The DC/DC converter temperature sensor B circuit signal is intermittent or erratic.
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 turns high-voltage battery power into lower-voltage power for vehicle systems. The control module watches temperature sensor B’s signal for sudden or unstable changes and sets P0C41 when the reading becomes intermittent or erratic. The converter may limit output because it cannot depend on that temperature reading.
Common causes
Most likely first.
- Loose or poor sensor connector
- Intermittent wiring fault
- Faulty temperature sensor
Symptoms
- Hybrid-system warning light may illuminate
- Intermittent reduction in power or hybrid operation
- DC/DC converter may limit output to protect itself
How to diagnose it
- Review freeze-frame data and live data for DC/DC converter temperature sensor B to identify any sudden jumps, dropouts, or frozen values.
- With the vehicle powered down as directed by the manufacturer, inspect sensor B’s connector for looseness, corrosion, moisture, or damaged terminals.
- Inspect sensor B’s wiring for rubbing, pinching, heat damage, or a loose harness section that may interrupt the signal with vibration.
- Monitor sensor B’s live reading while gently moving accessible wiring and the connector to see whether the signal drops out.
- Test sensor B and its circuit for intermittent continuity or unstable response using the manufacturer’s procedure, comparing with sensor A where appropriate.
Common fixes
- Secure or clean sensor B’s connector and repair damaged terminals.
- Repair intermittent wiring faults in sensor B’s circuit.
- Replace temperature sensor B if it intermittently fails its response test.
- Clear the code and confirm sensor B’s reading remains stable through a repeat operating cycle.
Can I keep driving?
Avoid long trips and heavy electrical loads while hybrid operation is intermittent or power is reduced. Stop safely if power drops sharply or a critical hybrid warning appears, since the converter may further limit output.
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.