What it means
The cell balancing circuit G reports a range/performance 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 G is the BMS-controlled path that adjusts charge in its assigned cell group. The BMS checks whether the G channel responds within its expected operating range when balancing is requested; this code means its response is outside that range, potentially because of the circuit, driver, or cell conditions.
Common causes
Most likely first.
- Balancing circuit or wiring fault
- BMS driver fault
- Cell-voltage or temperature condition affecting balancing
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 read live G-channel balancing status, cell-group voltages, and temperatures to identify when the response went out of range.
- Compare the G group’s readings with neighbouring groups and check for voltage or temperature conditions that could inhibit balancing.
- With the high-voltage system made safe under the vehicle’s procedure, inspect G-channel wiring and connectors for damage, corrosion, or poor contact.
- Test the G balancing circuit and switching component against the manufacturer’s procedure and specification.
- If the circuit passes, evaluate the BMS driver and the G group’s voltage and temperature inputs.
Common fixes
- Clean or secure a poor G-channel connector.
- Repair damaged G-channel wiring.
- Replace a faulty G balancing component if testing confirms it.
- Repair or replace the BMS if its G-channel driver fails testing.
Can I keep driving?
The vehicle may limit power or charging, so avoid long trips and do not rely on normal electric range. Stop if a battery warning, limp mode, or charging failure occurs, and arrange prompt diagnosis of the high-voltage system.
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.