What it means
The BMS detects a circuit 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 read a cell group in the high-voltage battery. This code indicates a general circuit fault on channel C, so the module cannot rely on that group’s voltage reading; it does not specify a low, high, or performance condition.
Common causes
Most likely first.
- Open or damaged voltage-sense wiring
- Loose or corroded connector
- 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 cell groups to identify a missing or implausible reading.
- With the vehicle powered down according to the manufacturer’s high-voltage safety procedure, inspect channel C’s accessible sense wiring for breaks, crushed areas, or damaged insulation.
- Inspect channel C connectors for loose seating, corrosion, or damaged terminals that could interrupt the circuit.
- Have a qualified technician test channel C continuity and connection resistance against the manufacturer’s procedure and specification.
- If the wiring and connectors pass, have the battery voltage-sensing module checked for a channel C circuit fault.
Common fixes
- Reseat and clean a loose or corroded channel C connector.
- Repair damaged or open channel C sense wiring.
- Restore a poor terminal or splice connection in the channel C circuit.
- Replace or repair the battery voltage-sensing module if testing confirms it is faulty.
Can I keep driving?
If the vehicle has reduced power, limp mode, or a high-voltage battery warning, avoid driving except as needed to reach a safe location because the system may limit propulsion or charging. Have it diagnosed promptly and do not access 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.