What it means
The BMS detects a circuit range/performance 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 measures a battery cell group using voltage sense channel K and checks that the reading behaves within an expected range. This code sets when channel K's reading is outside the expected range or performance window, even if the circuit is not simply registering as low or high.
Common causes
Most likely first.
- Sense voltage drifted
- High-resistance contact
- Sensor element aged beyond calibration window
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 K voltage with neighbouring channels across the conditions captured, looking for a persistent offset or drift.
- With the vehicle powered down following the manufacturer's high-voltage safety procedure, inspect channel K wiring and connectors for corrosion, looseness, or damage that could add resistance.
- Check whether channel K's reading changes abnormally during charging or operation compared with adjacent cell-group readings, using manufacturer diagnostic guidance.
- Have a qualified hybrid/EV technician measure channel K circuit resistance and signal against manufacturer specifications.
- If the wiring and connector pass, have the BMS measurement input and calibration checked before concluding that a sensing element or module has aged out of range.
Common fixes
- Clean and secure a high-resistance channel K connector.
- Repair or replace damaged channel K wiring causing voltage drop or drift.
- Replace a failed channel K sensing component if testing confirms it is out of calibration.
- Replace a faulty BMS only after the channel K signal path and calibration have been checked.
Can I keep driving?
A channel K reading outside its expected performance range can lead the BMS to reduce power or limit charging. Avoid relying on full electric range or making demanding trips until diagnosed, since continued operation with an unreliable cell-group reading can trigger further restrictions.
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.