What it means
The negative contactor C of the battery charging system reports a control circuit high 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 switch in the battery's high-voltage charging path. The control module monitors its control-circuit voltage and sets this code when the signal is higher than expected. A short to battery positive, an open contactor coil, or poor connector contact can leave the circuit high.
Common causes
Most likely first.
- Control wire shorted to B+
- Open contactor coil
- Connector pins corroded - high contact resistance
Symptoms
- Hybrid or EV system warning
- Charging may be disabled
- Vehicle may not start or enter Ready mode
How to diagnose it
- Record freeze-frame data and related codes, then check live data to verify the negative contactor C circuit is being reported high.
- With the vehicle powered down as specified by the manufacturer, inspect the contactor C harness for a short to a power wire, rubbed insulation, or heat damage.
- Check the connector for corrosion, loose terminals, or pins that are pushed back and may interrupt the circuit.
- Using the manufacturer's high-voltage safety and isolation procedures, test the control circuit for an open or short to battery positive and compare coil condition with the manufacturer's specification.
- If wiring and coil checks pass, follow the manufacturer's procedure to test the contactor driver and module input.
Common fixes
- Repair a control wire shorted to battery positive.
- Clean or repair corroded or loose contactor C connector terminals.
- Replace negative contactor C if its coil is open or outside the manufacturer's specification.
- Repair the control driver or module if testing confirms it is causing the high reading.
Can I keep driving?
Avoid driving if the vehicle cannot enter Ready mode, and do not rely on charging while the warning is active. The high-voltage charging path may be unavailable, leaving the vehicle unable to start or recharge.
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.