What it means
The cell balancing circuit L reports a stuck off condition. Cell-group voltage equalization may be impaired on this channel.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Balancing circuit L helps equalize the voltage of the battery cell group assigned to channel L. The battery management system monitors whether the L path responds when it requests balancing. This code sets when the L path is detected as inactive despite a balancing request, leaving that group less able to equalize.
Common causes
Most likely first.
- Open balancing switch or circuit
- Open or damaged balancing-circuit wiring
- BMS driver fault
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
- Review freeze-frame data and live battery-management readings for the L balancing request and the voltage of its assigned cell group.
- Compare the L group’s voltage with neighbouring groups while balancing is requested to check whether the expected equalization is absent.
- With the high-voltage system made safe under the vehicle’s service procedure, inspect the L connector and harness for an open, loose, corroded, or damaged connection.
- Test the L balancing switch and circuit wiring for continuity and poor connections using the manufacturer's procedure and specification.
- If the circuit tests correctly, have the battery management system driver and its L-channel output checked.
Common fixes
- Repair an open or damaged wire or connector in the L balancing circuit.
- Replace a failed L-channel balancing switch or circuit component.
- Repair or replace the battery management system driver if testing shows it is not activating L.
Can I keep driving?
The vehicle may restrict propulsion or charging, so avoid long trips and situations where reduced power could create a hazard. If charging fails or limp mode starts, stop safely and arrange prompt service; continued driving can allow the L cell group to become more imbalanced.
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.