What it means
The ECM detects a circuit fault on the drive motor a inverter voltage sensor b circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Drive motor A's inverter voltage sensor B monitors voltage in the inverter that supplies the motor. This code sets when the sensor B circuit signal is higher than the module expects, so the reading cannot be trusted for motor control.
Common causes
Most likely first.
- Sensor failed
- Wiring or connector fault
Symptoms
- EV/hybrid system warning light on
- Reduced motor power or torque
- Possible limp mode or vehicle shutdown
How to diagnose it
- Record freeze-frame data and live sensor B readings with a scan tool, checking whether the high signal accompanies reduced motor torque or a warning.
- With the high-voltage system made safe, inspect sensor B's connector and wiring at drive motor A's inverter for damage, looseness, corrosion, or contact with a power feed.
- Check the sensor B signal circuit for a short to power or an open, following the wiring diagram and manufacturer's specification.
- Verify connector contact and the sensor circuit's reference and ground where specified to rule out a wiring fault causing the high reading.
- If the wiring passes, test sensor B and the inverter input before deciding whether a sensor or module has failed.
Common fixes
- Reseat or repair a loose or corroded sensor B connector.
- Repair wiring shorted to power or an open circuit.
- Replace drive motor A inverter voltage sensor B if the circuit tests correctly but the signal remains high.
- Repair the inverter or control module if its specified tests confirm an internal fault.
Can I keep driving?
Reduced motor power or torque may progress to limp operation or a shutdown, so avoid driving if power is limited or the vehicle behaves unpredictably. Arrange prompt diagnosis, and do not handle inverter wiring unless the high-voltage system has been made safe.
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.