P0B0B: Electric/Auxiliary Transmission Fluid Pump A Motor Supply Voltage Circuit High
What to do
Ask whether any other overvoltage codes are stored. This code on its own is usually a wiring or measurement fault; alongside others it points at the charging system, which is a different and more urgent repair.
What this code means
The pump motor's supply is reading higher than expected.
Two readings, and they are not equally likely. The commoner is that the supply is fine and the measurement is wrong — a sense wire shorted to a live circuit, or a reference fault making a healthy rail look high. The rarer is a genuine overvoltage from the charging system, which would normally be flagged by its own codes and would not confine itself to one pump.
So the first question is whether anything else is reporting high voltage. Alone, this points at the circuit; in company, it points at the supply everything shares.
Likely causes
Start here
- Wiring shorted to voltage · moderate
Less common
- Charging system overvoltage · moderate
- Corroded or loose connector · easy
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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