P0BF5: Drive Motor B Phase V Current Sensor Circuit

What it means

The current sensor for drive motor B phase V reports a circuit fault. Phase current measurement is unreliable.

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 controls three motor phases and uses a current sensor to monitor the W phase. This code sets when the drive motor B phase W sensor circuit has a fault, so the control module cannot reliably determine current in that phase.

Common causes

Most likely first.

1. Current sensor failed
2. Wiring fault

Symptoms

• EV/hybrid system warning light on
• Reduced motor power or torque
• Possible limp mode or vehicle shutdown

How to diagnose it

1. Record freeze-frame data and check live drive motor B phase W current sensor values and related inverter codes to identify when the fault occurs.
2. With the high-voltage system made safe according to the manufacturer's procedure, inspect the phase W sensor connector and harness for damage, loose pins, corrosion, or chafing.
3. Check the phase W sensor signal, supply, and ground wiring for opens, shorts, and poor connections using the manufacturer's wiring information.
4. Compare drive motor B phase W readings with phases U and V under equivalent conditions to establish whether the fault is specific to W.
5. If wiring checks pass, test the drive motor B phase W current sensor according to the manufacturer's diagnostic procedure.

Common fixes

• Clean and secure a loose or corroded phase W sensor connector.
• Repair damaged, open, or shorted wiring in the drive motor B phase W circuit.
• Restore a poor sensor supply or ground connection.
• Replace the drive motor B phase W current sensor if it fails testing with verified wiring.

Can I keep driving?

If power is reduced or limp mode is active, avoid demanding driving because the vehicle may further limit motor output or shut down. Stop safely if a shutdown warning appears or drive is interrupted.