What Does P0BF1 Mean?
This code indicates a general circuit malfunction in the Phase U current sensor for Drive Motor B. In a dual-motor hybrid or EV configuration, Motor B is typically the secondary drive unit (often the rear motor). The control module has detected that the Phase U current sensor signal is erratic, missing, or outside the expected operating range, preventing accurate motor control.
Safety Warning
Loss of accurate Phase U current sensing on Motor B compromises torque control for that motor. The vehicle may disable Motor B entirely, significantly reducing available power and regenerative braking capability. Avoid highway driving until resolved.
Common Causes
30%
Failed Phase U current sensor in Motor B inverter assembly
25%
Damaged or corroded wiring between the sensor and Motor B controller
20%
Loose or disconnected connector at the Motor B Phase U sensor
15%
Motor B inverter module internal circuit fault
10%
Sensor reference voltage supply issue from the Motor B controller
Diagnostic Steps
1
Scan for additional DTCs related to Motor B — multiple phase sensor faults suggest a controller or common power/ground issue rather than a single sensor failure.
2
Access Motor B live data and monitor Phase U current readings; compare against Phase V and Phase W for balance during motor operation.
3
Inspect the Motor B Phase U current sensor connector for physical damage, water intrusion, or corroded terminals.
4
Verify the 5V reference voltage and signal ground at the Phase U sensor connector with the key on, engine off.
5
If the sensor is integrated into the inverter module, check for technical service bulletins regarding inverter sensor failures for the specific vehicle model.
6
Perform a controlled motor test (if supported by the scan tool) to exercise Motor B and observe all three phase current readings in real time.
Estimated Repair Cost
$400 - $2,800
Parts + labor, varies by vehicle and location
This code indicates a general circuit malfunction in the Phase U current sensor for Drive Motor B. In a dual-motor hybrid or EV configuration, Motor B is typically the secondary drive unit (often the rear motor). The control module has detected that the Phase U current sensor signal is erratic, miss...
The most common cause of P0BF1 (Drive Motor "B" Phase U Current Sensor Circuit) is: Failed Phase U current sensor in Motor B inverter assembly
Typical repair costs for P0BF1 range from $400 to $2,800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of accurate Phase U current sensing on Motor B compromises torque control for that motor. The vehicle may disable Motor B entirely, significantly reducing available power and regenerative braking capability. Avoid highway driving until resolved.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0BF1 to identify the root cause.
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Quick Info
Category
Powertrain
System
Hybrid/EV Drive Motor System
Difficulty
Type
Generic (SAE)
Recommended Tools
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