P0B0A: Electric/Auxiliary Transmission Fluid Pump A Motor Supply Voltage Circuit Low
What to do
Fix this one before agreeing to any other transmission work — a pump running on low voltage generates misleading faults elsewhere, and chasing those first is how a small wiring repair turns into a large bill. The measurement that matters is taken at the pump while it is running; a reading at the fuse box proves nothing.
What this code means
The pump motor's supply is present but sagging below what it should be.
Low supply is worse than it sounds, and P0882 already carries the argument in its most expensive form: a motor starved of voltage does not stop, it misbehaves — running slowly, producing less pressure than commanded, and provoking faults that name perfectly healthy parts downstream. So this code deserves to be fixed before anything else in the transmission is believed.
The usual causes are resistance somewhere in the feed rather than a failure at either end: a corroded joint, an undersized repair, a connector that has lost tension. Measure the voltage at the pump with the pump running, not at the fuse.
Likely causes
Start here
- Corroded or loose connector · easy
- Low system voltage · moderate
Less common
- Damaged transmission wiring harness · moderate
- Voltage drop from corroded pump connections · moderate
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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