P0D7A: Air Conditioning Compressor Motor Phase U Current Low
What to do
Air conditioning will be weak or absent, and on a heat-pump car so will heating. The compressor may be audibly rough. The car drives normally, but an unbalanced motor damages itself, so this should not be left.
What this code means
The current in one of the compressor motor's three phases is outside its expected range.
The compressor's motor is three-phase, and its three currents are measured separately for a reason worth knowing.
A three-phase motor is fed by three windings energised in rotation, and in a healthy machine the three currents are equal in magnitude and evenly spaced in time. So the comparison between them is diagnostic in a way no single reading is.
One phase wrong is the motor or its driver — a shorted or open winding, a failed transistor in that leg of the inverter, or a connection on that phase. All three wrong together is the supply or the load: the direct-current feed, or a compressor that is mechanically hard to turn.
This is the same structure as the traction motor's phase codes at P0A5D and P0BE5, and the reasoning transfers directly — including the identity that lets the module audit itself, since three phase currents in a balanced motor must sum to zero at every instant.
Phase U is carrying less current than the other two. Usually an open or high-resistance winding on that phase, a failed driver in that leg, or a connection — all of which leave the motor running unevenly, which is audible as a rougher note and felt as reduced cooling.
Likely causes
Start here
- Faulty electric air conditioning compressor · specialist
- Corroded or loose connector · specialist
Less common
- Motor winding insulation breakdown · specialist
- Damaged wiring harness · specialist
Rare
- Incorrect compressor oil in a high voltage system · 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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