What Does P0C03 Mean?
This code indicates that Drive Motor B is drawing less current than expected for the commanded torque and operating conditions. Low current on Motor B means it is not producing its expected share of propulsion power, which in a dual-motor configuration affects total available power and vehicle dynamics. The fault may be caused by an electrical issue in Motor B, its inverter, or the current measurement system.
Common Causes
25%
Motor B inverter power stage degradation limiting current delivery
25%
Motor B phase winding high-resistance connection or partial open circuit
20%
Bus current sensor for Motor B under-reading due to drift
15%
Motor B controller imposing current limit due to a secondary fault or thermal protection
15%
High-voltage battery pack voltage sag under load limiting available current to Motor B
Diagnostic Steps
1
Review freeze-frame data for Motor B current, speed, temperature, and torque command at fault time, as well as battery voltage and state of charge.
2
In live data, compare Motor B current draw against Motor A during equal torque requests — Motor B should match Motor A proportionally; a significant deficit confirms the fault.
3
Check for additional DTCs related to Motor B phase sensors (P0BF1-P0BFC), the high-voltage battery, or thermal management that could explain current limiting.
4
Measure Motor B phase winding resistances — all three phases should be equal and within spec; elevated resistance in one phase limits total current.
5
Verify the high-voltage DC bus voltage at the Motor B inverter under load to ensure adequate supply voltage.
6
Inspect Motor B inverter high-current connections, bus bars, and fuse links for corrosion, heat damage, or excessive resistance.
Estimated Repair Cost
$400 - $3,500
Parts + labor, varies by vehicle and location
This code indicates that Drive Motor B is drawing less current than expected for the commanded torque and operating conditions. Low current on Motor B means it is not producing its expected share of propulsion power, which in a dual-motor configuration affects total available power and vehicle dynam...
The most common cause of P0C03 (Drive Motor "B" Current Low) is: Motor B inverter power stage degradation limiting current delivery
Typical repair costs for P0C03 range from $400 to $3,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Reduced Motor B current means less propulsion power, affecting acceleration capability and potentially AWD balance. Regenerative braking from Motor B will also be reduced, increasing reliance on friction brakes. Avoid demanding driving conditions until diagnosed.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0C03 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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