Brake Warning on DIC

[rez0nance]

Hey guys,

I've been having an issue lately where a Brake warning shows up intermittently and randomly on the DIC, and only stays on for a second before going away. Today was the third time it's happened, and it happened after I took a right turn aggressively. I believe the first 2 times it was after a hard brake.

The warning on the DIC is an exclamation mark within a circle with the word "Brake" under it. It's almost identical to the one you get when you apply the parking brake while moving, except that one says "Parking Brake" instead of just "Brake".

I'm getting no CELs when this happens, and having Onstar run a scan after the second time it happened turned up nothing. I checked my brake fluid and it's between the min and max marks.

Any ideas? I was thinking at first (given that it has happened after high-g maneuvers) that maybe the brake fluid got sloshed to the side or something, hence the warning going away after a second. However, as I said, my brake fluid is at the halfway point between min and max, so I dunno about that theory.

Given that the light doesn't stay on, I'm not TOO worried about it, but I'd really like to figure out what's going on. The manual just states to go to the dealer, who in turn will probably tell me they can't reproduce it.

[BlueJacket]

Maybe a loose wire connection at one of the hubs?

[rez0nance]

Maybe a loose wire connection at one of the hubs?

Hmm, do we have some kind of sensors at the hubs? I figured we'd have maybe one to check brake fluid level, if that. Granted that's just my hypothesis, as I have no idea really.

BTW, just to add, I haven't seen any symptoms in terms of braking performance. I tried a few hard stops to test it out, and nothing seemed wrong.

[BlueJacket]

Hmm, do we have some kind of sensors at the hubs? I figured we'd have maybe one to check brake fluid level, if that. Granted that's just my hypothesis, as I have no idea really.

BTW, just to add, I haven't seen any symptoms in terms of braking performance. I tried a few hard stops to test it out, and nothing seemed wrong.

Maybe I am wrong but we should have sensors in or around the hubs for ABS.

[rez0nance]

Maybe I am wrong but we should have sensors in or around the hubs for ABS.

Ah good point... Interestingly enough though, there is actually a dashboard light for ABS as well as a separate DIC warning for it (according to the manual), but I'm not getting that at all, just the "Brake" one.

[wreckwriter]

ABS DIC warning says "ABS Fault"

[rez0nance]

ABS DIC warning says "ABS Fault"

Yeah, definitely not what I'm getting.

Has this not happened to anyone else before?

[-Ray-]

If you have a few miles on your G8 expect a little pad wear. As the pads wear the fluid level drops. It's possible it's hitting the fluid level limit on occasion.

[rez0nance]

If you have a few miles on your G8 expect a little pad wear. As the pads wear the fluid level drops. It's possible it's hitting the fluid level limit on occasion.

That makes a lot of sense. So we for sure have a fluid level sensor then?

I guess the best way to check would be to add some fluid and see what happens... Problem is, stainless steel brake hoses are one of my planned mods for the near future, and that requires bleeding the brake fluid. Maybe it's a sign that I should get moving on that mod sooner?

Who am I kidding, what response would I expect from you guys? ;)

[Crazy Paul]

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/brakes/BrakeW1_05.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/brakes/BrakeW3_03.jpg
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/brakes/BrakeW4_04.jpg
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/brakes/BrakeW5_02.jpg

Except look on the left side of the firewall.

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/brakes/BrakeW2_03.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/brakes/BrakeW6_03.jpg

[rez0nance]

[whole lot of awesome info]


Awesome!!! Thanks a lot Paul! That's definitely very helpful!

FYI, it happened again a little while ago as I was driving back to work. This time, it was in a straight line, not during any aggressive maneuvers, and it stayed on longer (maybe 5 seconds, for a second I thought it was going to stay on constantly this time). I felt no symptoms in braking feel or braking performance at all.

I'm thinking it's probably a fluid level issue, but going by the Master Cylinder Reservoir filling instructions above, it seems filling it when it's above the minimum level mark isn't recommended, so I'm at a bit of a loss.

I'm going to give the sensor a closer look to see if it's loose or something, but given that this issue happens intermittently, I sort of doubt that would be the case.

[wreckwriter]

I keep mine filled to max with no issues (yet).

[rez0nance]

I keep mine filled to max with no issues (yet).

What do you think about the SS brake line install though? Seeing as I'd have to bleed the system for that, would I be wasting brake fluid by adding it before then?

[wreckwriter]

What do you think about the SS brake line install though? Seeing as I'd have to bleed the system for that, would I be wasting brake fluid by adding it before then?

Yea but mere drops. Losing the warning would ease your mind enough to be worth it I expect...........

[rez0nance]

Yea but mere drops. Losing the warning would ease your mind enough to be worth it I expect...........

Yeah good point...

I might just order the SS lines soon and get the swap over with just to kill 2 birds with one stone.

[miamio96]

I'm not sure of you warrenty status, but another angle is that if you put in the SS lines, the dealer will blame the install on the light even if they can reproduce it.

[rez0nance]

Just realized I never updated this thread...

So the warnings got more and more frequent to the point where they were coming on every time I started the car, and every time I released the brakes after anything more than light braking.

I took it to the dealer on a Saturday a few weekends ago, which was their short day (short staff as well, only one of their 2 service writers work, alternating Saturdays). Service writer that was there told me they were going to be closing soon, but came outside with me and took a look. After being amused with his astonished look at my Roto-Fab engine bay ("That's not stock huh?"), I showed him the brake fluid level being midway between the marks, even though I was getting the warnings. He basically repeated everything you guys said, about brake pad wear causing the fluid to drop and tripping the sensor. Said I should add a little bit of fluid, and that I could bring it by during the week to have them service the brakes (sure thing...).

Now the annoying part, it seems like nobody down here sells DOT4 brake fluid! The parts department at my dealer didn't have it (I wonder what would have happened if I did intend to take my car to them for brake service...), auto parts stores didn't have it. Got tired of looking so I put it off.

This past weekend I finally got fed up with the constant warnings so I asked my buddy if I could borrow some of his DOT4 that he recently bought on Amazon. Met up with him, filled the reservoir up until just under the neck (wasn't easy to check the level on new, clear fluid). No more warnings!

Something I was curious about given the difficulty in seeing the level on the clear fluid, what's the possible danger in overfilling the brake reservoir?

Also I'm starting to hear a constant squealing from one of my passenger brakes lately (sounds like it might be the rear, but not sure), so my pad/rotor replacement project just got bumped up in priority... I'll add the SS lines and speed bleeders at the same time.

[-Ray-]

There's no danger to over filling except to make a mess. The fluid is not supposed to expand.

[rez0nance]

There's no danger to over filling except to make a mess. The fluid is not supposed to expand.

Cool, good to know. Thanks for the info Ray!

[zepcom]

Also I'm starting to hear a constant squealing from one of my passenger brakes lately (sounds like it might be the rear, but not sure), so my pad/rotor replacement project just got bumped up in priority... I'll add the SS lines and speed bleeders at the same time.

Wonder if debris along the guide pins or something on that squealing passenger brake caused it to stick at some point, resulting in uneven wear (like that set of pads is near end-of-life where all 3 other corners are not) .... that could have been the reason your resovoir was somewhat low, and pulling off a few tires and comparing remaining pad thickness may prove or disprove a stuck pad.

I had that on one of my Grand Prix's back in the day, one aftermarket replacement pad's tolerances were just a tad too tight which made the pad not slide well along the guide pins, resulting from a stuck pad, down to rivits, and a replacement rotor and brake job needing to be done shortly thereafter.

But that got me thinking of your issues and this thread, and thought I'd contribute. Can't hurt to check the pads, perhaps they're fine, shoot the rotors and pad surface with brake clean spray and perhaps even your newly found 'squeak' will disappear!

Good luck! :cool2:

--zep

[rez0nance]

Wonder if debris along the guide pins or something on that squealing passenger brake caused it to stick at some point, resulting in uneven wear (like that set of pads is near end-of-life where all 3 other corners are not) .... that could have been the reason your resovoir was somewhat low, and pulling off a few tires and comparing remaining pad thickness may prove or disprove a stuck pad.

I had that on one of my Grand Prix's back in the day, one aftermarket replacement pad's tolerances were just a tad too tight which made the pad not slide well along the guide pins, resulting from a stuck pad, down to rivits, and a replacement rotor and brake job needing to be done shortly thereafter.

But that got me thinking of your issues and this thread, and thought I'd contribute. Can't hurt to check the pads, perhaps they're fine, shoot the rotors and pad surface with brake clean spray and perhaps even your newly found 'squeak' will disappear!

Good luck! :cool2:

--zep

It's definitely a possibility... Either way I was planning on upgrading to Hawks Ceramics and DBA 4000 slotted rotors on all 4 corners, so I'm not worried about keeping the stock components any longer. When I replace them I'm sure I'll find out the whole story...

[zepcom]

It's definitely a possibility... Either way I was planning on upgrading to Hawks Ceramics and DBA 4000 slotted rotors on all 4 corners, so I'm not worried about keeping the stock components any longer. When I replace them I'm sure I'll find out the whole story...

Glad this turned out to be the case and you got it fixed! Dirty pins = uneven wear.