P0A64 code meaning
Drive Motor A Phase W Current Low
Powertrain system Generic code P0Axx codes Check engine light
What P0A64 means
P0A64 means phase W of drive motor A shows too little current at the moment it should peak, typically an open W lead or a W sensor stuck at zero. GM completes its three-phase sequence with this code on the 2016 Chevrolet Volt motor control processor and in the 2018 hybrid tables: when the rotor sits within 30 degrees of the W phase axis, the inverter runs normal PWM above 50 V and the squared current command exceeds 900 A2 (2016) or 4,900 A2 (2018), a W peak below 9 A for 0.4 s of a 0.6 s window sets P0A64 as Type A, MIL on the first trip. Because the rotor passes each axis in turn, only the open phase is flagged. A Caterpillar patent uses a near-zero phase reading the same way. P0A65 is the high side, P0A5E and P0A61 cover U and V.
P0A64 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1.5 to 8 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0A64
- MIL and propulsion system warning
- Uneven or reduced electric drive torque
Common causes of P0A64
- Most likelyOpen circuit in the phase W cable, connector or terminal
- PossiblePhase W current sensor reads zero
- PossiblePhase W switch of the inverter not conducting
- Less likelyOpen winding of phase W in drive motor A
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Drive motor a phase wInverter
What each part of P0A64 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A | Area: hybrid propulsion. |
| 64 | The exact fault in that area. |
What to do next
- Note P0A64 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0A64
What does P0A64 mean?
P0A64 means "Drive Motor A Phase W Current Low". P0A64 means phase W of drive motor A shows too little current at the moment it should peak, typically an open W lead or a W sensor stuck at zero. It is a generic code, so it means the same on every make.
Is it safe to drive with P0A64?
Drive gently and only to a workshop. With P0A64 the car can go into limp mode (reduced power) to protect itself.
Will P0A64 fail an emissions test?
Yes, it can. P0A64 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0A64 to fix?
Difficulty: workshop only. A typical repair takes 1.5 to 8 hours of work. This is a job for a workshop.
Will P0A64 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.