Another ABS, VCS, yellow brake light warning question

Hi all,

2006 Prius. 145k miles. Replaced hybrid battery around 105k miles. Replaced 12v battery a few years ago.

My daughter drove it to work at 7 am this morning in Pennsylvania on the first cold morning (55-60) in a long time. Yellow emergency brake light (!), ABS and VCS lights all came on for about 30 seconds as she backed out of the driveway and went to work. She has about a 10 minute drive and said as she parked the car and reversed to fit better into her parking spot they came back on again. (This was all told after she returned home from work). She ran an errand after work 8 hours later (and 80+ degrees out) and another 15 minutes worth of driving and no lights.

After she was home, I tested the new-ish battery (3 years?) and it was 12.7v in the trunk with the car off, 12.1v in accessory mode (in the trunk and in the maintenance screen) and 14.2v when the car was turned on.

Front brakes were redone a year or two ago but a local mechanic and dealer did the rear rotors(?) about two months ago. The coolant control value was also replaced - the one that controls the heater vs AC system not the inverter one.

I just took it for a 15 minute drive and it seems fine. Brakes are good, slamming on them stops the car quick, no softness, etc. No lights at all. The hybrid battery was low when I started (2 bars) but gained a few as I drove. Trying reverse a couple of times (out of the driveway, in a parking lot, etc.) also showed no lights.

I've read a bunch of the threads and the paperclip technique to get the brake codes but thinking of just taking it to the dealer for them to check it out. I don't want to mess around with a car my 17 year old drives.

With the lights off will the dealer be able to get any codes? Or do I need to wait for the lights to come back on again? We are reluctant to have her drive it at this point and she's back to school in 2 weeks in any case.

Any thoughts/suggestions/opinions?

Thank you very much!

 

Thank you. The car has been sitting for an hour or so and when we turned it on there was definitely a 10 second rattling noise that stopped. The engine kicked on at the same time and was on for 20-30 seconds then stopped. After that there was a whine in the engine compartment that did not stop. Here's a video link to that noise:

Dropbox - IMG_0274.MOV - Simplify your life

Whine was constant for several minutes or more.

We turned the car completely off and back on again a couple of times and there was no rattling noise again.

A slowly dying brake actuator maybe? If I went to Autozone/Advanced Auto Parts/etc. would I get a code that would help diagnose the issue?

Thank you again.

Edit: the other thing I would add is when I was driving it and slammed on the brakes I did manage to make the tires squeaked like they were skidding(?). It didn't feel like the ABS thump-thump-thump braking if that makes sense.

 

Our dealer appointment is Thursday and will post the results. One question not answered: if the lights are off with the brake computer still have failure codes to report?

my daughter has admitted she may have driven once or twice with the parking brake on for a while

 

The only code my dealer could read off the brake computer was a historical faulty brake switch sensor. "There's no guarantee it will fix the problem" but their recommendation was to try a new switch. $250.

 

Heh, I think it's a great diagnostic! It could be your-brake-actuator-is-dead code(s) and we want $3k+ to replace it and I need to junk the car. And buying a new/used car right now is painful. We have been looking around the past week and amazingly little inventory everywhere.

This is a car my 17-year old drives mostly and the last thing I want is her to get stranded somewhere because the brake sensor dies fully and then the car won't start because it doesn't sense the brake is being pressed. Or her brake lights don't work during a drive.