After starting and then driving my H3 for about 30 seconds the brake fluid warning light will come on. Then after another 30 seconds or so of driving the traction control light will come on. Then after another minute or so of driving, they will both go off for the duration of the drive. Brake fluid level is full. Brake pads are at 50% or more. Visual inspection of speed-sensor wires appeared to be good. I have an OBD two scanner and there are no codes.I live down in Baja Mexico and am without a realscanner. Has anyone successfully dealt with this issue? Thanks,

 

Brake fluid level sensor in the reservoir sticking? When was the last time you bled the brakes and flushed the whole system with fresh fluid?

 

"Visual inspection of speed-sensor wires appeared to be good. I have an OBD two scanner and there are no codes."
A visual inspection is nice but will not convey much. You'll want to test each wheel speed sensor for proper electrical signals. A oscilloscope is your friend here.
Agree on brake fluid and sensor.

 

Thanks for your replies. I’m not sure the fluids ever been changed. Will a cleaning of the reservoir and change of fluid typically fix this problem? Or since everything is drained, should I go ahead and change out the sensor?

 

No guarantee it will fix the problem, but its an easy maintenance item that can cause this sort of thing if its been neglected. IMHO, there is no need to replace the sensor unless you know for sure that it's not working. It's not an item that would normally wear out, so I'd be surprised if its gone bad, and I believe its integral to the reservoir so not a cheap/easy fix. Brake fluid should be flushed every couple of years because it absorbs moisture over time, so if you aren't sure when it was last changed you should do that regardless as a preventative maintenance item and see if it makes your problem go away.

 

Thank you NMH3… I’ll do the flush and keep my fingers crossed. Appreciate the info!

 

So I went to flush the brake fluid, but the reservoir is extremely dirty and I think the best thing would be to remove it to clean it. I can’t find the procedure for removing just the reservoir. Doesn’t appear to be very straightforward.Can anybody help me with this?

 

https://schwarttzy.com/wp-content/up...akes-1-4-1.pdf - See pg 74. Manual says to remove the master cylinder first.

 

I wouldn't go to the trouble to try and remove/clean the reservoir. In the grand scheme of things, your reservoir probably holds ~10% of the brake fluid cycling through the car. That'd be like removing the coolant reservoir, dumping it out, and then filling it back up thinking the issue will be fixed. Best bet is to bleed the system and add more fluid through the reservoir. Probably can be done in more than one way but it would require the removal of a brake line to drain the fluid that way.

Also, are you 100% positive there is no crack or issue in ANY of the four brake lines leading to your calipers? If nothing stands out, be sure to check underneath the rubber protective cover if possible. Might also want to review the post Error messages on dash: Fluid - Service - Stab Sys - Traction - Failed - Brakes. I posted a few times on that and included a few pictures when I had a major failure in my front driver's side wheel.

My brakes felt spongy, though, and it wasn't long after until I got all the dash warnings and then everything blew up on me. If you don't see any issues and just wanted to do something, get a turkey baster and start sucking out the dirty brake fluid from the reservoir and replace it with new fluid. It will take quite some time to transfer any significant amount this way, though. Suck some out, refill, drive 100ish miles, repeat the process.