2010 Prius Brake Booster Repair Question

Hi All,

I'm not great with cars, and it seems like this has been brought up a bunch on this form already, but I was hoping to get some more insight into my specific issue:

After leaving my car at the airport for a few days, I came back and the ABS, SLP, Brake, (!) lights were all on (see picture). It seemed like the braking was abnormal, though functional, and it wasn't charging as I braked. I took it to the mechanic who ran diagnostics and came up with code C1391 (see picture) and told me I would need the Brake Booster Master Assembly with Skid Control ECU replaced for ~$3200.

It seems I'm out of the window for the free replacement by Toyota, though the total mileage is < 150K

Three questions:

1) Does the diagnosis and suggested maintenance seem correct?
2) Is the brake booster different from the brake actuator?
3) I don't think it's worth it to pay $3200 given the value of the car, but is it still safe to drive? Is it just that the ABS won't work or am I putting myself in more danger?

Thank you!!

 

The mechanic said they checked the 12v