What it means
The BMS detects a circuit high fault on voltage sense channel B 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 B to measure a cell group in the high-voltage battery. This code sets when the channel signal is higher than the module’s expected range, making that group’s reported voltage unreliable.
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 voltage readings for channel B with neighboring cell groups to see whether B is unusually high or fixed at an implausible value.
- With the vehicle powered down under the manufacturer’s high-voltage safety procedure, inspect channel B wiring for damaged insulation or contact with a voltage source.
- Inspect channel B connector seating and terminals for corrosion, looseness, or signs of an open or high-resistance connection.
- Have a qualified technician test the channel B circuit for a short to voltage and check continuity using the manufacturer’s procedure and specification.
- If the wiring checks pass, have the battery voltage-sensing module evaluated against the manufacturer’s diagnostic procedure.
Common fixes
- Reseat or clean a loose or corroded channel B connector.
- Repair channel B wiring that is shorted to a voltage source.
- Repair an open or high-resistance connection in the channel B 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 the high-voltage battery warning is displayed; the vehicle may limit propulsion or refuse charging. Have the fault checked promptly and leave high-voltage 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.