What it means
The BMS detects a circuit high 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 uses voltage sense channel C to measure a cell group in the high-voltage battery. This code sets when the channel signal rises above the expected range, so that group’s reported voltage cannot be trusted.
Common causes
Most likely first.
- Sense wire shorted to voltage
- 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 is unusually high or stuck at an implausible value.
- With the vehicle powered down under the manufacturer’s high-voltage safety procedure, inspect channel C wiring for damaged insulation or contact with a voltage source.
- Inspect channel C connectors for loose seating, corrosion, or terminal damage that could cause an open or high-resistance connection.
- Have a qualified technician test channel C for a short to voltage and verify continuity using the manufacturer’s procedure and specification.
- If the wiring checks pass, have the battery voltage-sensing module checked for a channel C fault.
Common fixes
- Reseat or clean a loose or corroded channel C connector.
- Repair channel C wiring that is shorted to a voltage source.
- 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 the vehicle limits power or displays a high-voltage battery warning, since propulsion or charging may be restricted. Have it diagnosed promptly and leave high-voltage battery wiring to 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.