What Does P0A57 Mean?
Drive Motor B current sensor circuit is reading lower than the expected minimum threshold. The hybrid control module has detected that the current sensor monitoring the secondary electric drive motor is producing a voltage signal below specification, indicating a potential open circuit, failed sensor, or wiring fault. This prevents accurate motor torque control.
Common Causes
35%
Failed drive motor B current sensor (internal open circuit or degraded element)
30%
Damaged or corroded wiring/connector between sensor and hybrid control module
20%
Hybrid powertrain control module internal fault or corrupted calibration
15%
Poor sensor ground connection causing low reference voltage
Diagnostic Steps
1
Step 1: Monitor drive motor B current sensor PID in live data — verify the reading is below the minimum threshold (typically below 0.1V on the signal circuit). Compare with freeze frame data.
2
Step 2: Inspect the current sensor connector on drive motor B for corrosion, bent pins, moisture intrusion, or loose terminals. Clean and reseat the connector.
3
Step 3: Using a multimeter, backprobe the sensor signal wire at the hybrid control module connector — with KOEO, verify 5V reference supply is present and ground reads below 0.05 ohms resistance.
4
Step 4: Measure the current sensor output voltage directly at the sensor connector while commanding motor operation — it should produce 0.5V–4.5V proportional to current flow. If output is stuck low, replace the current sensor.
5
Step 5: If sensor output is correct at the sensor but low at the HCM, perform a continuity and resistance test on the signal wire between the sensor and HCM. Repair any open or high-resistance sections.
Estimated Repair Cost
$200 - $800
Parts + labor, varies by vehicle and location
Drive Motor B current sensor circuit is reading lower than the expected minimum threshold. The hybrid control module has detected that the current sensor monitoring the secondary electric drive motor is producing a voltage signal below specification, indicating a potential open circuit, failed senso...
The most common cause of P0A57 (Drive Motor "B" Current Sensor Circuit Low) is: Failed drive motor B current sensor (internal open circuit or degraded element)
Typical repair costs for P0A57 range from $200 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may enter reduced power mode or limp mode. Avoid highway driving until resolved as sudden torque limitations could create hazardous situations.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0A57 to identify the root cause.
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Quick Info
Category
Powertrain
System
Hybrid Drive Motor System
Difficulty
Type
Generic (SAE)
Recommended Tools
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