What it means
The ECM detects a low fault on the drive motor b inverter voltage sensor a 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
The drive motor B inverter voltage sensor A sends its signal through a circuit monitored by the control module. This code sets when that signal is lower than the module’s acceptable range, which can result from a signal pulled toward ground, a shorted sensor, or excessive resistance at the connector.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- 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
- Record freeze-frame data and check sensor A’s live reading alongside other motor B inverter and battery voltage data to confirm the low signal.
- With the vehicle powered down according to the manufacturer’s procedure, inspect the sensor A connector for corrosion, bent pins, moisture, or a loose fit.
- Trace the signal wire from motor B inverter voltage sensor A and look for damage or contact with ground.
- Using the wiring diagram, test the signal circuit for a short to ground and check the sensor’s reference and ground circuits.
- If the harness and connector pass, test sensor A against the manufacturer’s specification for an internal short.
Common fixes
- Clean and properly reconnect corroded sensor A connector pins where serviceable.
- Repair a signal wire that is shorted to ground.
- Restore a poor sensor ground or reference connection.
- Replace sensor A if it fails the specified test for an internal short.
Can I keep driving?
Limit driving because the vehicle may reduce motor B torque, enter limp mode, or shut down. If the warning is accompanied by unreliable propulsion, stop in a safe place and arrange service.
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.