What it means
The BMS detects a circuit high fault on voltage sense channel Y 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 Y to measure a group of cells in the high-voltage battery. It sets this code when the channel Y signal rises above the expected range, making that cell group's reported voltage unreliable.
Common causes
Most likely first.
- Sense wire shorted to higher voltage
- Reference regulator overvoltage
- 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
- Use a scan tool to save freeze-frame data and compare channel Y with the other battery voltage readings to see when it went high.
- Check whether the fault coincided with charging, reduced power, or a hybrid system warning.
- Have a qualified hybrid technician inspect channel Y's connector and wiring for corrosion, damaged insulation, loose terminals, or contact with a higher-voltage circuit.
- With the high-voltage system made safe using the manufacturer's procedure, test the channel Y sense circuit for a short to a higher-voltage source and excessive connector resistance.
- If the wiring checks out, check the reference regulator and channel Y readings against the manufacturer's specifications.
Common fixes
- Reseat the channel Y connector if it is loose.
- Clean or repair corroded channel Y connector terminals.
- Repair channel Y wiring that is damaged or shorted to a higher-voltage circuit.
- Repair or replace the reference regulator or battery sensing component if testing confirms it is causing the high reading.
Can I keep driving?
Limit driving if the hybrid warning is active, power is reduced, or charging is restricted; the vehicle may enter limp mode and electric range may fall. Seek prompt hybrid-system diagnosis, and stop safely if a red warning or major loss of power appears.
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.