What it means
The signals of the HV battery voltage and drive motor B inverter voltage do not correlate within the calibrated tolerance.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The control system checks whether high-voltage battery voltage agrees with the voltage reported by the drive motor B inverter. This code sets when those readings differ beyond the allowed correlation, potentially because a sensor has drifted, their ground references differ, or battery cells are becoming imbalanced.
Common causes
Most likely first.
- One sensor characteristic drifted
- Ground offset between channels
- Pack cell imbalance approaching service threshold
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 live battery voltage with drive motor B inverter voltage under the conditions that set the fault.
- Check related voltage readings and charging status for clues that the mismatch follows motor B’s inverter channel or the battery pack.
- With the vehicle powered down as specified by the manufacturer, inspect accessible connectors and grounds for the battery voltage measurement and motor B inverter sensor circuits.
- Use the wiring diagram to test both voltage signal paths and their ground references for poor connections or voltage offset.
- If the circuits pass, review battery-management cell-group data and test the relevant voltage sensors against the manufacturer’s specification.
Common fixes
- Repair a loose or corroded connection in the battery or motor B inverter voltage sensing circuits.
- Correct a poor ground connection causing an offset between the voltage channels.
- Replace the voltage sensor that fails its specified accuracy check.
- Service the battery pack if cell-group imbalance is confirmed.
Can I keep driving?
Limit driving if power is reduced, charging is restricted, or the warning persists, since the vehicle may enter limp mode. Charging or electric range may deteriorate, and the vehicle may limit propulsion to protect the high-voltage system.
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.