What it means
The BMS detects a circuit high 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 uses battery voltage sense channel G to measure a cell group. This code sets when the channel signal rises above its expected circuit level, making that cell-group voltage measurement unreliable.
Common causes
Most likely first.
- Short to voltage 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 nearby cell-group readings and note the conditions when it went high.
- Check the manufacturer's high-voltage isolation procedure before inspecting the battery sense circuit.
- With the battery isolated as specified, inspect channel G connectors and accessible wiring for damage, corrosion, loose terminals, or contact with a voltage source.
- Test channel G wiring for a short to voltage and check continuity and resistance using the manufacturer's procedure and specification.
- If the wiring and connector pass, follow the manufacturer's tests for the channel G sensing input and BMS control circuitry.
Common fixes
- Reseat a loose channel G connector using the specified isolation procedure.
- Repair damaged or corroded channel G connector terminals.
- Repair or replace channel G wiring that is shorted to voltage or has an open or high-resistance connection.
- Repair or replace the battery sensing or BMS circuitry if diagnosis confirms an internal fault.
Can I keep driving?
Avoid relying on normal electric drive or charging if the vehicle has reduced power or limp mode; the BMS cannot trust channel G's reading and may restrict battery use. Have it diagnosed promptly, and stop if power loss makes driving 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.