P0A1C: Drive Motor B Control Module Performance
What to do
If your hybrid's all-wheel drive comes from a rear electric motor, assume it is not available while this code is stored — adjust for conditions accordingly. Diagnosis order is the same as P0A1B: supply, earth and software before any module is replaced.
What this code means
The module controlling the second drive motor has failed its self-check.
Motor B exists on two-motor systems — most commonly the rear motor of an all-wheel-drive hybrid, or the second machine in a two-motor transaxle. Everything said at P0A1B applies here unchanged: supply and earth before the module, software before hardware, and a replacement that needs programming to the car.
One consequence is specific to this code: on hybrids whose rear axle is driven only electrically, losing motor B means losing all-wheel drive while the car otherwise behaves normally. A hybrid that has quietly become front-wheel drive in winter is worth treating as more than a warning light.
Likely causes
Start here
- Failed power or earth supply to the module · moderate
- Module software fault needing an update · specialist
Less common
- Faulty power inverter · 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.
- What actually fixed it — or that nothing did, which is worth knowing too.
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