What it means
The BMS detects a circuit range/performance fault on voltage sense channel G 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 BMS measures a cell group through battery voltage sense channel G and checks that the signal behaves within an expected range. This code sets when channel G's reading or response is outside that expected performance range, even if it is not simply low or high.
Common causes
Most likely first.
- Open, short, or excessive resistance in voltage-sense wiring
- Loose, damaged, or corroded connector
- Fault in the battery voltage-sensing or control circuitry
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 and BMS data, then compare channel G's reported voltage with neighboring cell groups and its change during the recorded operating condition.
- Review related battery codes and the manufacturer's diagnostic information to identify whether channel G is out of range under charging, driving, or another condition.
- Follow the high-voltage isolation procedure, then inspect channel G connectors and accessible wiring for corrosion, looseness, pin damage, or chafing.
- Test channel G wiring for open circuits, shorts, and excessive resistance using the manufacturer's procedure and specification.
- If the wiring passes, use the manufacturer's checks to assess the channel G sensing circuit and BMS input for inaccurate or inconsistent measurement.
Common fixes
- Reseat a loose channel G connector using the specified isolation procedure.
- Repair corroded, damaged, or poorly seated channel G terminals.
- Repair or replace channel G wiring with an open, short, or excessive resistance.
- Repair or replace the channel G sensing or BMS circuitry if testing confirms the reading fault is internal.
Can I keep driving?
Avoid depending on normal charging or electric range if the vehicle has reduced power or charging limits, since the BMS considers channel G's measurement outside its expected performance. Arrange diagnosis soon; continued operation may trigger further battery power restrictions.
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.