a_very_naudi_guy

The roads here in the St. Louis city are not plowed as they are very narrow and, last week, I had pulled onto the side where a massive snow drift/chunk of ice was sitting. I got out of the car and I could hear my electronic parking brake trying to adjust itself -- or whatever it does from time to time, squeeling and making noise -- but did NOT engage the EPB. Upon entering the vehicle I was greeted with flashing PARK BRAKE and BRAKE red lights on the dash. I had parking brake issues before in cold weather and was able to reset it by engaging the brake and releasing it. The left side no longer works (probably freyed + destroyed wiring as it can't talk to the computer for that side) but the right seemingly is okay.

I went to drive off and there was no 'drag' from the parking brake yet the lights continuted to flash and, over 5MPH or so, a loud obnoxious beep filled my cabin. It stopped after a few minutes but would start itself after stopping at a stop sign, light, what have you.

I checked and reset codes with Vag-Com to no avail. I tried engaging and dis-engaging the brake several times. Eventually, I disconnected the two 30-amp fuses for the parking brake. No more parking brake light light or MILs popping up; however, I still get "BRAKE" flashing on the dash.

I checked codes again and again in the ABS system but there is nothing to be found. I have seemingly great brake fluid pressure and the reservoir, while virtually impossible to tell if its at MAX or MIN line since the fluid is light yellow and the plastic is thick and aged, seems to be completely full as it over-flowed immediately when I tried to top it up with some Pentosin DOT-4 fluid. There's a filter cap at the top of the fluid reservoir underneith the main cap that has a screen and prevents particles from getting in. There was already fluid sitting ABOVE this, it seemed, and me putting a few millileters of fluid more only made it overflow.

So, I have a full parking brake reservoir (last flushed/changed less than a year ago by Audi) and I have plenty of pressure. We did recently swap out the FRONT brakes ourselves but it's been working fine up until I pulled onto that chunk of snow and ice and the PARK BRAKE light / MIL triggered.

Something else - perhaps a coincidence, but this had never happened before until the night the PARK BRAKE/BRAKE light problem happened - was I got a PARKING BRAKE LIGHT error on my little dash-board screen indicating perhaps one of the brake lights was malfunctioning. I turned the car off and back on, hit the brakes, and everything was working (of course the BRAKE light still flashing). So I'm not sure what to make of this.

Any ideas? What else would cause a flashing BRAKE light to appear non-stop on my 2004 A8L? Again, good braking pressure, no 'pull' to the sides when braking, brake fluid seems to be full, the parking brake fuses are disconnected and there are NO codes in VCDS in the ABS module.

As for the parking brake, the only code is that it can't talk to the left-side computer which it couldn't do before, anyway, yet it gave me no problems after I engaged it and re-engaged it. The vehicle seems intent on harassing me.

Thanks

Giovanni Giovino 6.0+6.0TT

Hello Naudi,
I am confused by this statement "So, I have a full parking brake reservoir" as the brake fluid reservoir has not to do with the electric parking brakes, if it is "squeeling and making noise" that's you first place to look, as when the electric motors can not adjust to sense pad thickness it throws a brake warning on dash, albeit the yellow brake symbol, you must have the red word "brake" flashing, again most likely do to the bad EB motor.

Mister Bally

One of your parking brake motors is seized. You verified it is the Left side motor. Remove it from the caliper and try to rotate it with your fingers or a socet and ratchet. If you free it and it rotates, Fill the cavity with WD-40 and let it soak in for 5 min. Dump out and refill. Reinstall the motor and see if it works. I did this over two years ago and it has worked fine ever since.

Automotive_Buff

@a_very_naudi_guy I'll concur and say it's a seized motor.

It happened to me 3 years ago and was a pain to open up and diagnose.

I found the motor finally as I couldn't post it on your last thread but here's what mine looked like.

As I explained in your last thread, the motor has a pulley system with a set of gears.




Carefully try to rotate the mechanism by hand. You should feel some resistance. If you don't and you can spin it freely, the pulley system has slipped off the gears. If it creaks or grinds, then you're in my past situation of a broken gear assembly.

I tried looking for gears and assemblies for the parking brake motor but it's a sealed system and most people don't know about it. If it has damaged gears then I'm afraid you'll have to look at buying a used motor. If it has simply slipped off then you can carefully pry the pulley over the gearing with a flat head screwdriver or a pin nose screwdriver and reseal the system.

a_very_naudi_guy

Thanks for the detailed answers guys, but I am not sure I was being entirely clear; I am referring to the "BRAKE" light, right under "PARK BRAKE", that is flashing. I got rid of the parking brake (EPB) MIL and dash lights by removing the two 30 fuses from the trunk. Without a doubt my EPB has problems. However, the 'BRAKE' light stays on after I disabled the parking brake by way of the fuse removal (and code clearing as well) and just flashes my entire drive. It beeps only once at start of the car and that's it.

I mention that everything is full-- when I said parking brake fluid reservoir I meant brake fluid reservoir. Great pressure and braking, we installed Bosch brakes, calipers looked great. No codes at all from vag-com related to the brake system in ABS module with the exception of the parking brake module giving codes about the motors.

But, the BRAKE light just flashes and flashes. Not sure what to do.

Thanks

Jack88

Removing the fuse presents its own set of errors. I'm sure the brake light comes on when there is an issue with the parking brake, I've only had errors there once, and it was from doing the brake pad reset wrong.

Mister Bally

Like Jack88 says, removing the fuses that power the EPB means you have no EMERGENCY Brakes.

This is why the Brake warning (red) indicator is on and you get the hideous warning sound whenever you go above 3 MPH from below 3 MPH.

.If your hydraulics fail and you are on say, I-90 near downtown Cleveland at "Dead Man's Curve" going 50 or more MPH, your only hope is to pull up on the parking brake switch which will engage the rear brakes at full force in a pulsing fashion (don't want them to lock as the car would immediately spin around 180° where locked wheels want to become the forward most wheels). Removing those fuses defeats your safety net. Best to fix the parking brake immediately. Get the car home or to a shop but don't keep driving it. I had to drive home from Battle Creek, MI with it alert mode as one motor jammed (in the unlocked position thank goodness) and used a spare care (VW Beetle) until I could disassemble the parking brake motor to repair. Fortunately, no cracked gear and the WD-40 pool is still working.

As for the rear wheels locking at highway speeds and the vehicle spinning around 180°; Believe me, I've done a boatload of vehicle testing with Anti-Lock braking systems since 1985 to see this happen. You can demo this with a toy truck that has rubber wheels on a slanted piece of wood. Better still, a car with manual parking brakes in a parking lot or field with no poles or anything or anybody else to hit. Go 40 MPH straight and fully engage the parking brake. Enjoy the ride. Be sure the car does not have a high center of gravity. Otherwise, install training wheels first.