P0A66: Drive Motor B Phase U Current
What to do
As P0A5D, plus the rear-motor notes: expect all-wheel drive to be unavailable, and expect the cable run under the car to be the first thing worth looking at. High-voltage cabling — professional inspection only.
What this code means
The current in phase U of the second drive motor is wrong.
The three-phase argument at P0A5D applies to this machine whole — three circuits that must agree, the four suspects, the insulation test that sorts them. Motor B's own additions are the familiar pair from its other families: its cables may run underfloor to a rear axle, where damage is likelier and inspection easier to justify, and losing it usually means losing all-wheel drive rather than the car.
Likely causes
Start here
- Damaged high voltage phase cable or terminal · specialist
Less common
- Motor winding insulation breakdown · specialist
- Faulty power inverter · specialist
- Faulty motor current sensor · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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