What it means
The BMS detects a circuit high fault on voltage sense channel I 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
Voltage-sense channel I reports a high-voltage battery cell-group reading to the battery management system. This code sets when the channel I signal is higher than expected, so the BMS cannot rely on that measurement.
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 data and compare channel I live voltage with adjacent cell-group readings to confirm the high signal.
- With the vehicle powered down according to the manufacturer’s procedure, inspect channel I wiring and connectors for damaged insulation, corrosion, loose terminals, or contact with a powered circuit.
- Have the high-voltage battery isolated using the manufacturer’s safety procedure before handling sense connections.
- Test channel I for a short to voltage and check its connector and wiring against the manufacturer’s specifications.
- If the harness is sound, test the channel I sensing and control circuitry for a high input fault.
Common fixes
- Reconnect and secure a loose channel I connector.
- Repair wiring or insulation shorting channel I to voltage.
- Replace damaged or corroded channel I connector terminals.
- Repair or replace faulty battery sensing or control circuitry if the wiring passes.
Can I keep driving?
The vehicle may limit propulsion or charging while the channel I measurement is untrusted. Keep driving to a minimum and stop safely if reduced power makes the vehicle difficult to control in traffic.
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.