Brake booster issue maybe?

Can anyone tell me if this is a common failure mode on a 2012 Prius and if the problem is what I think it is. When slowing down the brakes pulsate as if the rotors are warped, however at the same time when slowing down and sitting at a light I can hear what I think is the brake booster motor turning on every second or two. This morning both the traction control and TPS lights were on steady, tire pressure is fine in all wheels. My wife was in a hurry to get to work so I didn't have time to try to read any codes. Is this a common failure mode on the 2012 model, and is this a common symptom when the brake booster is failing?

 

It has about 80k miles, there is plenty of pad left but I haven't had time to put the calipers on the rotors or check for runout. It's my wife's car, I don't drive it that often and she wouldn't notice if one of the wheels fell off, so to me it started suddenly but I really don't know. I don't think it's the rotors because if I'm stopped at a light and slowly easy up on the brakes until it starts to creep, it creeps in surging (not quite jerky) motions as if either I'm lightly pumping the brake (I'm not) or the electric motor is turning on and off. It does not feel like the rotors to me. @Air_Boss do you have any suggested search terms for more reading on the remedy you were talking about?

 

Thank you very much for the info. Is this recall related? I entered the VIN into the Toyota recall finder and there were none listed for this car. How would I get the dealer to check for this?

 

Ok sweet thanks. Is there any way for me to determine first use without the dealers help? I really don't like our local dealer, I'll let them fix it for free but if I have to pay then it's going to a private shop.

 

The dealer service guy tells me it's still eligible for Toyota to cover it, if that's the problem, so I'm bringing it to the dealer. But this guy has lied through his teeth to me before so I'm half expecting then to say yes this is the problem but oops it's not covered. I'll update as we go, thank you again for the info!

 

It's definitely something wrong, my wife tells me the TPS light, ABS light and "BRAKE" lights are all on now and the pedal doesn't feel normal. This is a new development, but I'll let the dealer diagnose it then depending on if Toyota is going to cover it I'll let the dealer do it or take it elsewhere.

Idiotic side note that I just can't help but comment on: if my diesel truck has an emissions system problem, it will actually disable the truck, 5mph max speed, until it's fixed. But if a car has brake system problems you can apparently drive it until the brakes fail completely and you hit something, they don't care. Interesting that we as a society prioritized pollution over actually being able to stop. Sorry, I've been dealing with diesel exhaust issues on our other car so this was relevant in my garage.

 

Update it's showing the accumulator leak error code:

 

No,I read that code myself (did not clear it!), It's going to the dealer tomorrow morning.

Interesting side note, my wife said the brake pedal felt funny and I test drove it myself and in fact the regenerative braking has been disabled and that's why the pedal feels funny, you have to push it further than normal before it starts to slow down. But it feels normal once it starts braking.

 

It is if Toyota wants to pay for it, otherwise it's going somewhere else or I'll do it myself.

 

It's at the dealer now. The service rep guy tells me it was first driven in July 2012 so it should be within the allowable mileage and time for it to be covered by Toyota. He said it might take a few days and didn't mention anything about a back order on parts so I'm keeping my fingers crossed, I'll update as it goes. Thank you again to everyone for the info, I owe you guys a beer or two for potentially saving me a wad of cash!