What it means
The BMS detects a circuit range/performance fault on voltage sense channel H 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 reads a cell group through battery voltage sense channel H and checks whether the signal remains within an expected performance range. This code sets when channel H's reading or response falls outside that range, rather than indicating only a low or high circuit level.
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 H's reading with adjacent cell-group readings and how it changes under the recorded conditions.
- Review related battery codes and manufacturer's diagnostic information to determine when channel H falls outside its expected range.
- Use the manufacturer's high-voltage isolation procedure, then inspect channel H connectors and accessible wiring for corrosion, loose terminals, pin damage, or chafing.
- Test channel H wiring for opens, shorts, and excessive resistance using the manufacturer's procedure and specification.
- If wiring and connectors pass, follow the manufacturer's checks for inaccurate measurement in the channel H sensing circuit or BMS input.
Common fixes
- Reseat a loose channel H connector using the specified isolation procedure.
- Repair corroded, damaged, or poorly seated channel H terminals.
- Repair or replace channel H wiring with an open, short, or excessive resistance.
- Repair or replace the channel H sensing or BMS circuitry if testing identifies an internal performance fault.
Can I keep driving?
If power is reduced or charging is limited, do not count on normal electric range while the BMS considers channel H's measurement out of range. Arrange diagnosis soon because battery power restrictions may continue or increase.
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.