What it means
The BMS detects a circuit low fault on voltage sense channel C of the high-voltage battery. Cell-group voltage measurement is unreliable on this channel.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery management system reads a cell group through voltage sense channel C. This code sets when the channel signal falls below the expected level, making the reported voltage for that group unreliable.
Common causes
Most likely first.
- Sense wire shorted to ground
- Open or high-resistance connection in the sense circuit
- Fault in the battery voltage-sensing module
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Save freeze-frame data and compare live channel C voltage with neighboring groups to see whether C reads abnormally low or drops out.
- With the vehicle powered down under the manufacturer’s high-voltage safety procedure, inspect channel C sense wiring for damaged insulation or a short to ground.
- Check channel C connector seating and terminals for corrosion or looseness that could create an open or high-resistance path.
- Have a qualified technician test channel C continuity and check for an unintended path to ground using the manufacturer’s procedure and specification.
- If the circuit passes, have the battery voltage-sensing module tested for a channel C measurement fault.
Common fixes
- Reseat or clean a loose or corroded channel C connector.
- Repair channel C wiring that is shorted to ground.
- Repair an open or high-resistance connection in the channel C sense circuit.
- Replace or repair the battery voltage-sensing module if testing confirms it is faulty.
Can I keep driving?
Avoid driving if power is reduced, limp mode is active, or a high-voltage battery warning appears; the system may restrict propulsion or charging. Arrange prompt diagnosis and do not access the battery’s high-voltage wiring yourself.
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.