What it means
The ECM detects a range/performance 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 changes high-voltage battery power to the lower voltage used by vehicle electronics and the auxiliary battery. The ECM monitors temperature sensor C and sets this code when its signal is electrically plausible but outside the expected range or inconsistent with converter operating conditions.
Common causes
Most likely first.
- Sensor characteristic drifted
- Sensor mounting displaced
- Sensor element aged beyond calibration window
Symptoms
- Hybrid/EV system warning light may turn on
- Reduced power or charging performance
How to diagnose it
- Save freeze-frame data and compare sensor C’s live temperature with other converter temperature readings and the vehicle’s operating state.
- Inspect sensor C’s mounting and connector to check that it is seated correctly and positioned as intended.
- Look for wiring damage, corrosion, or a loose connection that could distort the reading without causing a complete circuit failure.
- Compare sensor C’s response as the converter warms or cools with the manufacturer’s specification.
- If the wiring and mounting are sound but the reading remains out of range, test or replace sensor C and then recheck live data.
Common fixes
- Reseat temperature sensor C in its proper mounting position.
- Secure the connector and repair damaged or corroded terminals.
- Repair wiring that is altering the sensor reading.
- Replace sensor C if its response remains outside the manufacturer’s specification.
Can I keep driving?
Limit driving if the hybrid/EV warning appears with reduced power, and avoid demanding acceleration or relying on charging until the reading is checked. The vehicle may restrict converter operation to protect the system.
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.