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Can I borrow a haldex ecu please..

Discussion in 'A3/S3 Forum (8L Chassis)' started by quattrokid, Jun 5, 2013.

  1. quattrokid
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    quattrokid Active Member

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    [Jun 5, 2013]
    Our S3 has an "Awesome" haldex ecu upgrade which is believed to be causing issues with the abs...

    Basically what's happening is this:

    It first appeared on our way home from collecting the car in January, sat on the motorway plugging our way home when... up came the yellow triangle & abs warning lights in the dash !!

    Stopped en route for fuel and the 2 warning lights didn't reappear, in fact they didn't reappear for a few weeks.....

    Took it to our local Audi master techy chappy who scanned it only to find no fault codes on the car whatsoever *:scratch: *so we left it at that... out on a country drive doing 40 mph when the lights reappeared !!

    a pheasant decided to fancy its chances and ran into the road, so I braked quite hard, the brake pedal felt like it was pulsing and dropped nearly to the floor *:shock: *it felt as if I was braking on dry tarmac onto gravel!!

    At higher speeds the brakes are spot on BUT the brake pedal does feel much softer than our previous S3 some 7 years ago now, maybe I'm so used to the UrS4 & RS4 brakes I "think" the pedal is soft but I'm sure it should feel harder to push than it is....

    New discs and pads fitted this week has made no difference, the wheel abs rings and sensors have all been double checked, so have the vacuum hoses. No faults came up on the vag com block for the abs or brakes so all is good there. The brakes have been checked and the fluid changed twice within a few days, still no difference...

    without going into changing the abs module/ pump assembly the only other thing we can think of is this Awesome haldex ecu

    It's programmed to be more of a 50/50 drive instead of whatever %age split a normal haldex ecu does ( the haldex has had its 40'000 mile oil & filter change put the symptoms persist)

    Does anyone have a spare 2001 S3 8L comparable ecu I can borrow please and see if this is the culprite ?

    Basically the abs is kicking in early at slower speeds and it's un nerving when the car doesn't stop as it should :shock:

    Any help would be appreciated *:thumb:
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jun 5, 2013]
    The haldex controller has no influence over the brake pedal... they are not connected physically at all... if your pedal is sinking its something else...

    Haldex takes a feed from the throttle pedal and ABS controller so it can work out how and when to engage... all the performance controller does is change the reaction times to the data being fed to it...

    Pulling fuse 31 for the haldex controller will be a useful test... I suspect the braking issue will remain... haldex is not engaged under braking, only acceleration (when you need AWD)

    ABS related issues are typically abs sensor or wiring related.. if there are no fault codes coming up in the ABS module (assuming your audi tech scanned for everything... just because they are Audi trained don't assume they know what to look for) then there could be a wiring fault but... you describe the pedal sinking and this suggests a hydraulics/mechanical issue...

    I don't believe for one minute that if lights came on the dash there would be no codes... the lights come on as a result of a fault... these faults WILL be logged...

    Get yourself a copy of VCDS and a cheap ebay cable (info on this is in the stickies) and scan it yourself..

    <tuffty/>
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  4. quattrokid
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    quattrokid Active Member

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    [Jun 5, 2013]
    hi Tuffty,

    cheers for your reply, im going to get the car back and use it this weekend and see if any codes comes up on a friends vag com. I had the vcds lead from ebay BUT the car wouldnt accept it because its not an original ross tech lead :(

    i'll take it to another guy nearer to Mum's whos pretty clued up with these cars, see what he says, canny do much on the phone, he needs to Mk1 eyeball it
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  5. kwistof
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    kwistof South East Events Moderator Regional Rep

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    [Jun 5, 2013]
    When the ABS feels like it's kicking in early- is this with the ABS light on the dash board?

    I had huge trouble with my ABS control module for ages and spent hundreds of pounds at different places to get it sorted.

    Has the longitudinal and latitudinal sensors been changed? I realise you have had the car scanned but sometimes those faults are not stored to check afterwards.

    Also if you are asking for help mate- maybe you should put where your located, as the U.K is a pretty large place :)
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  6. quattrokid
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    quattrokid Active Member

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    [Jun 5, 2013]
    hello Kwistof :) yes the lat & long sensors have been checkand are ok... abs feels like coming on early even with no dash lights illuminated, going to try the fuse 31 trick later..

    oh im in Aryshire, Scotland... i'll go and update my profile :)
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  7. kwistof
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    kwistof South East Events Moderator Regional Rep

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    [Jun 5, 2013]
    Hiya.....Hmmm yeah that is strange one indeed..... I cannot remember the exact fault code or description that came up with my issue, but I know it was finally down to the ABS controller getting intermittent signals. I ended up replacing pretty much everything as well fella and was driving without any ABS for a good 9+ months with the bloody symbol on the dash all the time! lol

    The garage I went to sent the ABS unit to these guys, as no 'regular' garage would be opening up ABS control modules and fixing them and provide a guarantee.

    (Drop me a PM if you want the company)

    As you can see from my location I'm wayyyyyy too far to help with the Haldex bud- but as Tuffty has already pointed out, I also would be extremely shocked if it was down to your performance Haldex upgrade.
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  8. quattrokid
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    quattrokid Active Member

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    [Jun 5, 2013]
    the first owner ( we're the second) had it fitted, to be honest it doesnt feel any different from the first S3 we had ! a 600 quid gimmick as far as I can see !!

    yea... Kent is a bit far for a meet up over a coffee !! lol I am watching an ABS module/ controller on ebay at the moment, my techy chappy thinks that IF there was an issue with the controller it would put up a code on vag com ? its a big job to replace then find out its not the problem, from here on in its an expensive gamble whichever way we turn so might just leave it for now and enjoy the car..... due its mot in Aug so it needs bushes replaced for that!! its only done 42k miles!! what did it cost you you to get your abs controller opened up and fixed? isnt it an exchange item with the freindly (!!) dealer ?
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