What it means
The BMS detects a circuit low fault on voltage sense channel K 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 BMS reads a battery cell group's voltage through sense channel K. This code sets when channel K's signal falls below the expected range, so the BMS cannot rely on that reading to assess the cell group.
Common causes
Most likely first.
- Sense wire shorted to ground
- Open in sense wire
- Connector pins corroded - high contact resistance
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
- Record freeze-frame data and check live channel K voltage against neighbouring channels to confirm whether the low reading is specific to K.
- With the vehicle powered down following the manufacturer's high-voltage safety procedure, inspect the channel K sense wire and connectors for damage, corrosion, or moisture.
- Check that channel K connector pins are clean, seated, and secure, because corrosion or poor contact can pull the signal low.
- Have a qualified hybrid/EV technician test channel K wiring for a short to ground or an open circuit using the manufacturer's procedure.
- If the wiring passes, have the BMS channel K input and reference supply checked against manufacturer specifications.
Common fixes
- Clean and secure corroded or loose channel K connector pins.
- Repair an open or damaged channel K sense wire.
- Repair a channel K wire shorted to ground.
- Replace a faulty BMS only after channel K wiring and reference checks pass.
Can I keep driving?
The BMS cannot reliably assess the cell group monitored by channel K, so power may be limited and charging may be reduced or stopped. Avoid long trips and hard acceleration until diagnosed, and stop safely if a battery warning says to stop.
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.