What it means
The negative contactor C of the battery charging system reports a circuit 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 control module monitors its circuit and whether the contactor responds to commands; this code sets when it detects a fault in that negative-contactor circuit.
Common causes
Most likely first.
- Contactor failed
- Wiring or connector fault
Symptoms
- Hybrid or EV system warning
- Charging may fail or stop
- Vehicle may not enter Ready mode
How to diagnose it
- Read freeze-frame data and related codes to see when the negative contactor C circuit fault occurred and whether other charging-path faults were logged.
- Check scan-tool command and feedback data for negative contactor C, if available, and note whether charging or Ready mode was being requested.
- With the vehicle powered down under the manufacturer's high-voltage safety procedure, have a qualified technician inspect the negative contactor C connector and accessible wiring for damage, corrosion, or looseness.
- Have the technician test the negative contactor C control and feedback wiring for continuity and poor connections as specified by the manufacturer.
- If the wiring is sound, have the technician test negative contactor C's coil and switching response using the manufacturer's procedure.
Common fixes
- Repair a loose, corroded, or damaged negative contactor C connector.
- Repair an open or damaged negative contactor C control or feedback wire.
- Replace negative contactor C if it fails its coil or switching tests.
- Repair the module circuit if testing isolates the fault there.
Can I keep driving?
Charging may fail or stop, and the vehicle may not enter Ready mode. Avoid depending on it for a trip until its charging and start-up behaviour is confirmed; high-voltage contactor work should be handled by a qualified technician.
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.