What it means
The BMS detects a circuit low 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 falls below its expected range, so the reported voltage for that cell group cannot be trusted.
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
- Use a scan tool to save freeze-frame data and compare channel Y with the other battery voltage readings to see when it dropped low.
- Check the battery and hybrid system warnings and note whether power reduction or charging limits occurred with the fault.
- Have a qualified hybrid technician inspect channel Y's sense-wire connector and wiring for corrosion, damage, poor seating, or contact with ground.
- With the high-voltage system made safe using the manufacturer's procedure, test the channel Y sense wire for a short to ground, an open, and excessive resistance.
- If wiring and connections pass, compare channel Y readings with the manufacturer's specifications and assess the battery management system or cell group for an internal fault.
Common fixes
- Reseat the channel Y sense connector if it is loose.
- Clean or repair corroded channel Y connector terminals.
- Repair or replace channel Y wiring that is open, damaged, or shorted to ground.
- Replace or repair the battery sensing component identified by testing if channel Y still reads low.
Can I keep driving?
Avoid demanding acceleration and long trips if power is reduced, charging is limited, or the hybrid warning is active; the vehicle may enter limp mode or lose electric range. Arrange 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.