P0C08: Drive Motor B Phase U-V-W Circuit/Open
What to do
As P0C05, plus motor B's particulars — expect all-wheel drive to be unavailable, and expect the underfloor bundle to be the first place worth looking.
What this code means
All three phase circuits between the inverter and drive motor B are faulty or open.
The all-three-at-once argument — that three phases failing together points at what they share rather than at three faults — is at P0C05. Motor B's usual particulars apply: it is normally the second machine, its loss costs all-wheel drive rather than the car, and its phase bundle runs underfloor where damage is both likelier and easier to find.
Likely causes
Start here
- Corroded or loose connector · specialist
- Damaged high voltage phase cable or terminal · specialist
- Chafed harness between transaxle and inverter · specialist
Less common
- Faulty power inverter · specialist
- Motor winding insulation breakdown · 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
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
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.
- What actually fixed it — or that nothing did, which is worth knowing too.
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