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Brake warning light after a cold night

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by Craig Cull, Oct 7, 2012.

  1. Craig Cull

    Craig Cull Well-Known Member

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    Hi all, dunno if anyone's had the same problem, but since the weather started getting a little colder, I've found when I start the car 1st thing in a morning (in the garage) after a cold night, I get the brake warning light for about 10 seconds, then it goes off and doesn't come back on until a similar weather event occurs. My pads and discs are fine, brake fluid level is fine, does anyone know what's going on?? The pedal is always hard and it stops on a penny. Any chance this could be moisture getting onto the brake pad sensors? Or do I have an issue that's more serious than that? Has anyone experienced the same issue? Any help would be great, brakes are one thing I don't take any gambles with. :/
     
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  3. ukdan

    ukdan Member

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    Battery needs charging or is on its way out.
    For some reason, when it's harder to start the car like in the winter months a failing battery doesn't give out as much cranking amps and the car doesn't like it.
     
  4. Craig Cull

    Craig Cull Well-Known Member

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    cheers ukdan, but I've only recently had a new heavy duty battery fitted. It's as I turn the ignition on, before I start the engine, then stays on for 10 seconds ish
     
  5. hades-

    hades- Yorkshire & Humber Rep.
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    does it bleep 3 times
     
  6. Craig Cull

    Craig Cull Well-Known Member

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    yes mate, but then the light goes off
     
  7. hades-

    hades- Yorkshire & Humber Rep.
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    im sure theres a fix for that on here
    james will prob be along and post the link i think its james that knows
    but its either low batt or the fix will sort it
    iv had it on a few audis in the cold weather.
     
  8. Craig Cull

    Craig Cull Well-Known Member

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    ok bez that's brill, hopefully it will be the fix as I've just spent £100 on a new heavy duty battery bout 2 months ago, you may remember my previous post, lost loads of power while the ecu reset.
     
  9. Craig Cull

    Craig Cull Well-Known Member

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    Same issue again this morning, if nobody else has had this problem then I better get it into Audi ASAP, don't want me brakes failing! :/
     
  10. Boro&Beth

    Boro&Beth Member

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    I've started getting this on mine over the last couple of week. Assumed it was low pads/discs but haven't had time to check properly.

    Any more info would be good.
     
  11. ctd

    ctd Member

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    mine has just started doing the same
     
  12. Craig Cull

    Craig Cull Well-Known Member

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    i have been told by the mechanics at work that its something to do with the brake sensor being near the main wiring harness. Audi made something to fix this and apparently there's a shroud that goes around the brake sensor. I'm not sure how/why or if it solves the problem but its definitely worth a shot. So.... Next question, anyone know where to get one of these?? Or if what the mechanics saying sounds correct?
     
  13. Greeny233

    Greeny233 Active Member

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    I had exactly the same problem on mine last winter, I just lived with it. Still using the same battery now.
     
  14. murran

    murran Active Member

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    must be october, the seasonal phantom low brake fluid warning threads have started. lol.

    i'll still go with what i said last year...... its the brake fluid reservoir with its integral sensor/float system. something to do with the tiny bits of water and silt in the reservoir coupled with cold weather trip the sensor on start up. change the reservoir (the whole thing).
     
  15. Boro&Beth

    Boro&Beth Member

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    It's a low brake fluid warning?

    Not low pads as I thought originally?
     
  16. sidibear

    sidibear Looking for Zombies !!
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    In my experience one tends to go with the other, as the pads wear the brake piston has to go out that little bit further, and takes more fluid to do it, so as the pads get thinner, the piston comes out further and the fluid level gets lower.
     
  17. Craig Cull

    Craig Cull Well-Known Member

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    Yeah, my pads are fine and the brake fluid is all ok, I checked the basics before this post. That's why I'm confused
     
  18. murran

    murran Active Member

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    pad warning is yellow and looks like a circle with a pair of brake shoe linings inside it and just one beep.
    brake fluid warning is red, the same symbol as above but with an exclamation mark in the middle and three beeps.

    ive replaced maybe 5/6 reservoirs in the past for this exact fault on start up. non so far this winter yet tho.
     
  19. Boro&Beth

    Boro&Beth Member

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    Do you mean you replaced 5/6 reservoirs on your car before the fault went away or you've had the same fault on 5/6 different cars.
     
  20. Craig Cull

    Craig Cull Well-Known Member

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    Whats the average price for a reservoir?
     
  21. GarJE

    GarJE Member

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    Prise out the mesh filter. Did this to mine. Haven't had a warning since.
     
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  23. murran

    murran Active Member

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    i mean im a professional mechanic, working in a garage. and ive seen this fault 5/6 times on different a4s b6s and b7s. changing the reservoirs fixed them.
    think theyre 30/40 quid for the whole reservoir.
     
  24. V6 Quatt

    V6 Quatt Well-Known Member

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    Would you need to bleed the brakes again?? Or just a straight swap
     
  25. Craig Cull

    Craig Cull Well-Known Member

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    Even tho my brake fluid reservoir was full, I decided to top it up a touch. Problem solved! :)
     

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