What it means
The power supply circuit of drive motor B inverter reports a circuit low condition. Inverter operation may be impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Drive motor B's inverter depends on its supply circuit to power its control and switching functions. The control module sets this code when the monitored supply falls below the expected range, which can happen from a ground short, voltage drop under load or resistance at a corroded connection.
Common causes
Most likely first.
- Supply voltage collapsed under load
- Wire shorted to ground
- Connector pins corroded - high contact resistance
Symptoms
- EV/hybrid system warning light on
- Reduced motor power or torque
- Possible limp mode or vehicle shutdown
How to diagnose it
- Read freeze-frame data and related codes to see whether the low supply coincided with high electrical or motor load.
- With the vehicle safely powered down, inspect drive motor B inverter supply wiring and connectors for corrosion, damage or signs of contact heating.
- Check the supply terminals for corrosion or loose contact that could cause a voltage drop.
- Test the supply voltage under the conditions specified by the manufacturer and compare it with the manufacturer's specification.
- Check the circuit for a short to ground and measure voltage drop across the supply path to locate excessive resistance.
Common fixes
- Clean or repair corroded inverter supply terminals.
- Repair damaged supply wiring or a confirmed short to ground.
- Restore a loose or high-resistance connector connection.
- Repair the upstream supply fault if testing shows voltage collapses under load.
Can I keep driving?
Limit driving if motor power is reduced, and avoid situations where sudden loss of acceleration would be dangerous. The inverter may enter limp mode or the vehicle may shut down.
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.