What it means
The BMS detects a circuit intermittent/erratic 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 monitors cell-group voltage through battery voltage sense channel G. This code sets when the channel G signal becomes erratic or intermittent, preventing a stable, reliable measurement of that cell group.
Common causes
Most likely first.
- Loose or damaged voltage-sense connector
- Intermittent open or short in voltage-sense wiring
- Intermittent fault in the battery voltage-sensing 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, and note whether channel G's reading or the warning changes with vibration, temperature, charging, or driving.
- Follow the manufacturer's high-voltage isolation procedure before inspecting the battery sense circuit.
- Inspect channel G's connector for loose fit, damaged locking features, corrosion, or pin damage, and check accessible wiring for chafing or strain.
- Use the manufacturer's test procedure to check channel G wiring for intermittent opens or shorts while gently moving accessible sections of the harness.
- If the connector and harness test consistently, follow the manufacturer's checks for an intermittent fault in the channel G sensing input or BMS circuitry.
Common fixes
- Secure a loose channel G connector and verify its lock is engaged.
- Repair corroded or damaged channel G terminals.
- Repair or replace channel G wiring with an intermittent open or short.
- Repair or replace the sensing circuitry or BMS if testing identifies an intermittent internal fault.
Can I keep driving?
Intermittent channel G readings can make the BMS limit power or interrupt charging unexpectedly, so avoid long trips if warnings or reduced power occur. Arrange diagnosis promptly and stop if the vehicle's power loss makes it unsafe.
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.