What it means
The negative contactor C of the battery charging system reports a stuck open condition. HV charging path cannot be commanded reliably.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Negative contactor C is a high-voltage switch on the return side of the battery charging path. The module checks whether it closes when commanded; this code sets when the path remains open or feedback indicates open after a close command.
Common causes
Most likely first.
- Contactor contacts oxidised
- Contactor coil burned out
- Carbon or debris buildup preventing free movement
Symptoms
- Hybrid or EV system warning
- Charging may be disabled
- Vehicle may not start or enter Ready mode
How to diagnose it
- Read freeze-frame data and related codes to see when negative contactor C was commanded closed and what feedback the module recorded.
- Check charging and Ready status to confirm whether the vehicle failed to establish the charging path.
- With the vehicle powered down under the manufacturer's high-voltage safety procedure, have a qualified technician inspect negative contactor C's connector and accessible wiring for corrosion, looseness, or heat damage.
- Use scan-tool command and feedback data, if available, to compare negative contactor C's commanded state with its reported state.
- Have a qualified technician test the contactor coil and verify whether the contacts close when commanded, following the manufacturer's procedure.
Common fixes
- Clean or repair a corroded or loose negative contactor C connector and control wiring.
- Repair an open or damaged low-voltage control wire to negative contactor C.
- Replace negative contactor C if its coil has failed or its contacts do not close when commanded.
Can I keep driving?
The vehicle may not charge or enter Ready mode, so avoid setting out if you cannot confirm it will start and has sufficient charge. Have the high-voltage contactor fault diagnosed before relying on the vehicle.
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.