What Does P0C57 Mean?
This code indicates the signal voltage from drive motor "B" position sensor circuit "A" has fallen below the minimum threshold expected by the powertrain controller. This typically points to a short to ground, an open circuit in the signal path, or a failed sensor producing insufficient output. The motor controller cannot determine rotor position accurately, which will likely trigger reduced power mode or disable motor B entirely.
Safety Warning
A low sensor signal may cause the controller to miscommutate the motor, potentially resulting in loss of propulsion or uncontrolled torque output. The vehicle will likely enter a protective limp mode. Do not drive at speed until the circuit fault is repaired.
Common Causes
32%
Short to ground in the position sensor signal wiring
26%
Open circuit or broken wire in the sensor harness
22%
Failed position sensor with collapsed output signal
13%
Corroded or water-damaged connector causing high resistance to ground
7%
Faulty inverter control module input circuit
Diagnostic Steps
1
Check the position sensor connector for moisture intrusion, corrosion, or bent/backed-out pins.
2
Measure voltage at the sensor connector with the key on to verify the excitation supply is within specification.
3
Test for continuity and shorts to ground on each wire in the sensor circuit A harness between the sensor and the controller.
4
Measure the sensor output resistance across the sine and cosine windings to verify they are within manufacturer specifications.
5
If wiring is intact, substitute a known-good sensor (if feasible) or monitor live data while manipulating the harness to identify intermittent shorts.
Estimated Repair Cost
$300 - $1,800
Parts + labor, varies by vehicle and location
This code indicates the signal voltage from drive motor "B" position sensor circuit "A" has fallen below the minimum threshold expected by the powertrain controller. This typically points to a short to ground, an open circuit in the signal path, or a failed sensor producing insufficient output. The ...
The most common cause of P0C57 (Drive Motor "B" Position Sensor Circuit "A" Low) is: Short to ground in the position sensor signal wiring
Typical repair costs for P0C57 range from $300 to $1,800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A low sensor signal may cause the controller to miscommutate the motor, potentially resulting in loss of propulsion or uncontrolled torque output. The vehicle will likely enter a protective limp mode. Do not drive at speed until the circuit fault is repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0C57 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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