What it means
The BMS detects a circuit intermittent/erratic 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
The battery management system monitors channel I to measure a high-voltage battery cell group. This code sets when that circuit’s signal is intermittent or erratic, preventing a stable voltage reading.
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
- Record freeze-frame data and watch channel I live voltage for dropouts or sudden jumps compared with neighbouring groups.
- With the vehicle powered down as directed by the manufacturer, inspect the channel I connector for looseness, corrosion, damaged pins, or a poor fit.
- Have the high-voltage battery isolated under the manufacturer’s safety procedure before touching battery sense wiring.
- Check channel I wiring for an intermittent open or short using the wiring diagram and the manufacturer’s specified test method.
- If the connector and harness are stable, investigate the channel I battery sensing circuitry for an intermittent fault.
Common fixes
- Reseat and secure the channel I connector.
- Clean or replace corroded or damaged channel I terminals.
- Repair chafed wiring or an intermittent open or short in the channel I circuit.
- Repair or replace faulty channel I sensing circuitry if the harness checks out.
Can I keep driving?
The vehicle may intermittently restrict power or charging as the channel I signal drops in and out. Avoid long trips, and stop safely if propulsion becomes unpredictable.
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.