What it means
The BMS detects a circuit range/performance 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 uses channel I to measure a high-voltage battery cell group and checks whether the reading behaves within its expected range. This code sets when the channel I signal is outside acceptable performance limits even if it is not simply a fixed open or short.
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
- Record freeze-frame data and compare channel I live voltage with neighbouring groups over changing battery conditions to identify an implausible or drifting reading.
- With the vehicle powered down as specified by the manufacturer, inspect channel I wiring and connectors for corrosion, looseness, damage, or signs of high resistance.
- Have the high-voltage battery isolated using the manufacturer’s safety procedure before handling sense wiring.
- Test channel I wiring and connector resistance and check for opens or shorts using the wiring diagram and manufacturer’s specifications.
- If the circuit is sound, evaluate the channel I sensing input and battery monitoring circuitry for a reading that falls outside its calibration range.
Common fixes
- Secure a loose channel I connector and clean or replace corroded terminals.
- Repair high-resistance or damaged channel I wiring.
- Repair an open or short in the channel I sense circuit.
- Repair or replace faulty channel I sensing circuitry if the harness passes testing.
Can I keep driving?
Power may be reduced and charging may be restricted while the BMS cannot validate the channel I reading. Avoid long journeys or depending on full electric range, and arrange diagnosis promptly.
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.