What Does P0A64 Mean?
Drive Motor A Phase W current is reading below the expected minimum threshold. The hybrid control module detects Phase W stator current is abnormally low during motor operation, indicating a potential open winding, disconnected phase cable, failed current sensor, or non-switching IGBT on the Phase W leg.
Safety Warning
Loss of one phase causes dangerous torque pulsation and rapid motor overheating. Do not drive — tow to service.
Common Causes
35%
Open circuit in Phase W stator winding of drive motor A
25%
Phase W current sensor failure reading low within the inverter
25%
Disconnected or high-resistance Phase W power cable connection
15%
Inverter Phase W IGBT stuck open (not switching)
Diagnostic Steps
1
Step 1: Compare Phase W current with Phase U and V in live data — Phase W reading near zero while others are normal confirms a W-specific fault.
2
Step 2: With HV system de-energized, measure Phase W winding continuity from the motor terminal to neutral. An open reading confirms a broken winding.
3
Step 3: Inspect the Phase W cable and terminal connections for loose bolts, corrosion, or heat damage. Torque to specification.
4
Step 4: Test the Phase W IGBT pair in the inverter for opens using a multimeter on diode-check mode.
5
Step 5: Replace the faulty component and verify balanced three-phase operation with a controlled motor test.
Estimated Repair Cost
$500 - $3,500
Parts + labor, varies by vehicle and location
Drive Motor A Phase W current is reading below the expected minimum threshold. The hybrid control module detects Phase W stator current is abnormally low during motor operation, indicating a potential open winding, disconnected phase cable, failed current sensor, or non-switching IGBT on the Phase W...
The most common cause of P0A64 (Drive Motor "A" Phase W Current Low) is: Open circuit in Phase W stator winding of drive motor A
Typical repair costs for P0A64 range from $500 to $3,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of one phase causes dangerous torque pulsation and rapid motor overheating. Do not drive — tow to service.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0A64 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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