What it means
The ECM detects a intermittent/erratic 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
Drive motor B inverter voltage sensor A supplies a signal whose stability is monitored by the control module. This code sets when the reading jumps, drops out, or otherwise varies intermittently instead of tracking smoothly, often because the connector, wiring, or ground reference loses contact with vibration.
Common causes
Most likely first.
- Sensor connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
Symptoms
- EV/hybrid system warning light on
- Reduced motor power or torque
- Possible limp mode or vehicle shutdown
How to diagnose it
- Review freeze-frame and event data, if available, and watch sensor A’s live reading for dropouts while noting when the fault returns.
- With the vehicle powered down according to the manufacturer’s procedure, check that the motor B sensor A connector is fully seated and its pins are clean and secure.
- Inspect the sensor A harness and ground-reference wiring for loose terminals, chafing, strain, or damage that could move with vibration.
- Use the wiring diagram to test the signal, reference, and ground circuits for intermittent continuity or resistance changes while gently moving accessible harness sections.
- If the connections remain stable, test sensor A’s output against the manufacturer’s specification for erratic operation.
Common fixes
- Reseat and secure the sensor A connector.
- Repair loose or damaged terminals in the sensor A circuit.
- Repair a noisy or intermittent ground-reference connection.
- Replace sensor A if it continues to produce an erratic signal with sound wiring.
Can I keep driving?
Driving can trigger sudden power reduction or limp mode if the signal drops out again. Keep trips short and avoid situations where losing motor power would be hazardous; stop safely if the warning recurs with reduced propulsion.
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.