What it means
The BMS detects a circuit low fault on voltage sense channel X 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 X to measure a group of cells in the high-voltage battery. It sets this code when the channel signal falls below the 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 X 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 X'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 X sense wire for a short to ground, an open, and excessive resistance.
- If wiring and connections pass, compare channel X readings with the manufacturer's specifications and assess the battery management system or cell group for an internal fault.
Common fixes
- Reseat the channel X sense connector if it is loose.
- Clean or repair corroded channel X connector terminals.
- Repair or replace channel X wiring that is open, damaged, or shorted to ground.
- Replace or repair the battery sensing component identified by testing if channel X 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.