What Does P0C06 Mean?
This code indicates a low-voltage or short-to-ground condition in the Drive Motor A three-phase power circuit (U, V, W). The motor controller has detected that the phase voltage or current on one or more phases is abnormally low, suggesting a short to the vehicle chassis/ground, insulation breakdown in the phase conductors, or a motor winding short to the stator core. This is a serious electrical safety fault in the high-voltage system.
Safety Warning
A ground fault in the high-voltage motor circuit is an electrical shock hazard and a fire risk. The vehicle's isolation monitoring system should prevent operation, but the high-voltage system remains dangerous. Do not attempt to drive. Only qualified high-voltage EV technicians should diagnose this fault.
Common Causes
30%
Motor A stator winding insulation breakdown causing phase-to-ground short
25%
High-voltage phase cable insulation damage creating a ground fault
20%
Moisture intrusion into the Motor A terminal box or connector causing tracking to ground
15%
Inverter power stage low-side IGBT/MOSFET short circuit
10%
Contamination (coolant leak, debris) bridging a phase conductor to ground
Diagnostic Steps
1
Check for ground fault isolation monitoring DTCs — most EVs have an isolation monitor that can quantify the severity of the ground fault.
2
With the high-voltage system de-energized and locked out, perform phase-to-ground insulation resistance tests on all three Motor A phases at the motor terminal box.
3
Inspect the Motor A phase cables for physical damage, abrasion, pinch points, or areas where the insulation may have been compromised.
4
Check the Motor A terminal box and connectors for moisture, coolant contamination, or conductive debris that could create a ground path.
5
Measure insulation resistance at the inverter phase outputs to isolate whether the fault is in the cable, motor, or inverter.
6
If the motor has liquid cooling, check for coolant leaks that could be wetting electrical connections.
Estimated Repair Cost
$600 - $5,000
Parts + labor, varies by vehicle and location
This code indicates a low-voltage or short-to-ground condition in the Drive Motor A three-phase power circuit (U, V, W). The motor controller has detected that the phase voltage or current on one or more phases is abnormally low, suggesting a short to the vehicle chassis/ground, insulation breakdown...
The most common cause of P0C06 (Drive Motor "A" Phase U-V-W Circuit Low) is: Motor A stator winding insulation breakdown causing phase-to-ground short
Typical repair costs for P0C06 range from $600 to $5,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A ground fault in the high-voltage motor circuit is an electrical shock hazard and a fire risk. The vehicle's isolation monitoring system should prevent operation, but the high-voltage system remains dangerous. Do not attempt to drive. Only qualified high-voltage EV technicians should diagnose this fault.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0C06 to identify the root cause.
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Quick Info
Category
Powertrain
System
Hybrid/EV Drive Motor System
Difficulty
Type
Generic (SAE)
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