[nigelvh]

A few weeks ago, I was driving home from work on the freeway (with traffic, maybe 20-30MPH). Suddenly the "BRAKE" warning light started blinking at me.

I gently tested the brakes to make sure they worked. They did.

Next I pulled off the freeway, stopped, and turned the car off for a bit, then turned it back on. "BRAKE" light still blinking at me. Checked the manual, it just said to get it to a dealer. Since the brakes physically worked, and I grew up driving without power brakes I wasn't worried about that surprising me, I decided I'd drive straight to the dealer. (Not far from my home.)

So, about 15 or so minutes down the road, the "BRAKE" light decided "Oh, I'm fine. I'll stop blinking now and go out." Well... That's half reassuring...

Anyway, I ended up leaving it with the dealer the next day, and they ran a pile of tests. (Checked for codes three times, recalibrated the system, checked the fluid levels, checked that everything was working.) They couldn't find a single code, nothing wrong that they could find. (I'm sure they thought I was hallucinating the flashing "BRAKE" light.)

So, I've got no info from the dealer on why it might have happened, and it hasn't happened since. Does anyone here have any thoughts on what would cause the "BRAKE" light to blink for 20 minutes or so, then stop, and there be no codes in the system?

For reference, it's a 2012 Outback 2.5 Premium with Manual Transmission.

 

[Thunderchild]

When mine did that I needed new brakes. Did they even check your brakes?

 

[nigelvh]

I think they did, and the brakes work fine with no squeaks. Also, it would be rather odd to need new brakes 6-8 months after driving it off the lot.

 

[subiesailor]

Take a peek at the brake fluid level under the hood. Possible its a hair low or maybe a tad high.

A 2012 2.5 should run 50-60,000 miles fairly easily on the stock pads. Since it goes on and off - my suspicion is that its your fluid level being really close to a trip point and some cold weather is just enough to trip it - then it goes away after the car is warmed up or you have used the brakes a few times? Sound about right?

 

[subiesailor]

If you have a fault in the ABS sensors you will get an ABS light on the dash not a Brake light- this ABS fault will also disable your cruise control - it doesn't sound like that is the case for you. Brake fluid level is generally the cause of what you describe

 

[nigelvh]

The dealer checked the brake fluid level, and at the point the issue occurred, I had been driving for probably a half hour, and used the brake dozens of times. The car was certainly warmed up, and the temperature that day was mild, somewhere around 60-70.

Would the fluid level being low (or the sensor being odd) cause it to blink, or would it remain steady on?

 

[subiesailor]

The dealer checked the brake fluid level, and at the point the issue occurred, I had been driving for probably a half hour, and used the brake dozens of times. The car was certainly warmed up, and the temperature that day was mild, somewhere around 60-70.

Would the fluid level being low (or the sensor being odd) cause it to blink, or would it remain steady on?

Possible the dealer didn't get the cap back on right or disturbed the sensor connection on the top of the cap. Very easy to just look at it your self - it either looks right with the level showing between the low and high marks or the cap looks wonky and a simple reseating of the cap might solve it. Again this is text book brake fluid level tripping up the sensor or the cap not being on right.

 

[subiesailor]

The way brakes are designed they have two stages in the cylinder for redundancy as long as the pedal travel and feel has not changed your brakes are fine and the brake light indicator is like I said a fluid level issue or possibly the cap not being on strait etc.

 

[nigelvh]

No, the dealer looked at the level AFTER the blinking light happened. However, you're right that it could have not been seated right or had been disturbed.

The brakes work fine, and the issue hasn't recurred since. I'll look at the cap and sensor connection myself. But mostly I just want to know why it was blinking at me.

I grew up driving an '84 Subie Brat, and had to fix crap on it all the time. So it's not surprising that it could be that sensor. Just with these new cars being so computer controlled, and then the computer won't tell us anything about it, makes me wonder.

(One of my favorite memories of that car is seeing the look of horror on my fiance's face as I used the parking brake in lieu of the regular brake because I had to keep my foot on the gas to keep it from stalling.)

 

[subiesailor]

Yup this is pretty common actually after a brake job when the fluid level is goofy but in your case my suspicion would be the cap or the sensor in the top of the cap being disturbed in some manner by the shop tech

 

[plain OM]

Was the light flashing at a regular rate, like the turn signals would do, or was it sort of random or inconsistent on and off? If regular, then according to the Owner's Manual (page 3-17), if the Brake system warning light flashes

"the electronic parking
brake system may be malfunctioning.
Immediately stop your
vehicle in a safe location, use
tire stops under the tires to
prevent the vehicle from moving
and contact your SUBARU dealer.
For details, refer to “Electronic
parking brake” 7-34.".

Seems to me if the light was flashing regularly, it was probably related to this, rather than the brake fluid level sensor. A flashing Brake light indicates that a problem was detected related to the electronic parking brake and it was not working. (I believe that when the light is flashing, the hill holder function is also disabled.)

The FSM has a list of some 26 electronic parking brake control-related trouble codes, in C02## format, which should be readable using the Subaru Select Monitor. But some appear to clear if the problem disappears and/or if the ignition switch is turned to Off and then back on. Some of the possible causes of the flashing apparently could be due to the way the parking brake switch is used, faulty signals from the ECM, wrong power to the parking brake control module, CAN communications problems etc.

 

[cardoc]

Its just a shot in the dark here, but maybe, just maybe the park brake wasn't totally released or not all the way as far as the sensor on the park brake is concerned? On a lot of Japanese and European cars, if the park brake switch/sensor is telling the instrument cluster that the brake is set and to light the brake light, it would flash if you put it in gear and drove it to get your attention that the park brake is set and you are moving which could cause damage.

The park brake circuit wouldn't necessarily set an error code either.

And if its a circuit controlling the park brake and assist, it should be under warranty as a safety item and you should be sure that they checked all possible areas related to the park brake, the light, warning indicators and all factors underlying the flashing light. And be sure to keep record of it with detailed explanation of what the service department found or not. It may rear its ugly head in the future.

The great thing here is its a Subaru. The techs are trained to inform Subaru of any "oddities" they run across after a new build is released so it can be recorded, investigated and relayed to other service centers. The network is well organized and full of information. Someone else may have come across this already and has the answer and repair if necessary.

 

[nigelvh]

Yeah, it was not on steady, it was flashing regularly clearly a programmed warning, and not a random electrical contact causing it to flash a bit. I did look at the manual and read the same thing you did. I hadn't used the parking brake in probably a half hour, and the hill holder was not enabled.

I do save all my service documents, so I'll have the dealer's description from the document in case it comes up again, but in summary it says that they checked a whole pile of stuff, recalibrated the system, and couldn't find anything.

And in response to cardoc, you're absolutely right. I've had nothing but excellent service from my local subaru dealer. All the way from the zero pressure looking at the cars, through trying to find the best financing for me, to bringing it in for service and getting me in a loaner right away so they're not taking up my time.

I expect things will go wrong on any car. That the things are covered under warranty, and how the dealer treats me are far more important.