Brake Light Warning

There are several possibilities. I once had a brake caliper fail to release cleanly which generated a ton of heat. But you really need to have someone read the codes. Guessing can be very expensive and time consuming. If you're at all handy and have a Windows laptop, I'd suggest getting a mini vci reader and techtream software from Amazon of some such place so you can read the codes yourself an look them up. They cost like $20-30 or so. There are lots of threads here about them. The readers in auto parts places and generic shops won't read all the codes a Prius can have. This is the one I got. It's down to $14. I have an old Linux Laptop running Windows XP in Virtualbox and it works super.
Oops! Forgot the link.

 

welcome! for $45. ask them what trouble codes they read and post here. how many miles on her? how old is the 12v?
and shame on that dealer.

 

I thought about suggesting that, too. I was figuring that if they didn't learn anything, they didn't check the codes. But it still never hurts to ask. Good point, Bisco.

 

I'm kinda wondering what specific light is on. It wouldn't be the TPMS light would it? That's one that'll light, stay on constantly. 2007 is about the time TPMS sensors are starting to have dead batteries. If that's the case, in your shoes, I'd just ignore it, unless you have to have it resolved for some inspection.



The regular brake system warning light comes on every time the parking (emergency) brake is on. Maybe the sensor for that is out of adjustment? Just another possibility.

 

If one of the brake lights is on, there should be a code on one of the Prius' ECUs. It may be your mechanic is only reading standard OBD codes, and not the Toyota ECU specific codes (I would think a Toyota mechanic would understand this though). I would ask that the Toyota mechanic provide you the codes on the car. This should have been included in the $45 you paid to checkout the car.

If you want to read the codes yourself, you can do so by buying a $20 mini VCI cable and installing Techstream on a laptop. Do some searches on this topic on Prius Chat and google for more information.

Once you have the codes, you should be a few google searches away from an at least okay understanding the problem, and what if any repairs are needed. Post back with the codes.

 

Ok good to know.

An outside possibility, but: that light comes on when parking brake is applied, and is supposed to go off when parking brake is released. But maybe, the mechanism that detects parking brake position is not adjusted right? I've attached the parking brake inspection info, might be of help.

 

Mendel's comment is good here too. The only situations I can think of where a brake warning light would be on but you might not get a code is if the parking brake is on or not adjusted properly, or your brake fluid is low.

 

If it's the brake warning light that's on, and the parking brake light turns off as expected, the parking brake should not be causing the problem. Can you be clear about what light is on? See Mendel's above post with the different indicator lights.

 

I'm not 100% sure myself, will be driving later this morning and will check, but I think when you apply parking brake it's the brake symbol with exclamation mark (referred to in pic above as "brake system warning light") that goes on with parking brake application. In other words it's doing double-duty: warning of brake system problems and giving heads-up that parking brake is on.

 

Checked it out: on my Canadian 2010 Prius, when the car's running, if I apply the parking brake, I see "brake system warning light", this one: . Not sure about second gen US model though.

 

Dash warning lights Image by Momotaro posted Feb 26, 2017 at 3:41 PM

We are about 100 miles from home, and this problem has come up again. It's Sunday afternoon and all local service stations are closed. The brakes work but at a minimum level. A diagnostic reset fix the problem about a week and a half ago, but they did say that it probably would be the skid ECU that would eventually need replacing, and that would be between two and $3000. Looking at a white knuckle drive home. Any help would be greatly appreciated.

 

At first glance, salvaged skid control ECUs can be had on eBay for well under $100. If you're a DIYer, I'd spend some of those quoted thousands for a tow home and a rental car and have at it there. I would not drive the car.

 

These are the situations where you really want to have access, in the car ready to use, to the "Special Service Tool 09843-18040" or its real-world equivalent (a short piece of wire), to touch between the CG and TC pins on your diagnostic port, and post back about what blinks out on your VSC/BRAKE/ABS/((O)) lights.

Without that information, it's hard to even know whether you're putting off a fix that can keep for a while, or one you'd want to feel a sense of urgency about.

-Chap[/QUOTE]

 

We made it home safely.

Mechanic can't look at the car until Friday.

Good thing I can work from home.

[/QUOTE]

 

Momotaro, I have exactly the same dashboard light signature with my 2008 Prius that just popped up. In the middle of a drive, got 4 warning lights simultaneously, 1) BRAKE (typically goes on when emergency brake engaged), 2) Brake warning light that looks like a tire with an exclamation point, 3) ABS, 4) VSC.

What ended up being the problem? Checked the brake fluid and it was full. Thanks@

 

welcome!

get the trouble codes read at a dealer.