mondial t abs hiccups | FerrariChat

mondial t abs hiccups

Discussion in 'Technical Q&A' started by nationofzeros, Apr 29, 2007.

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  1. nationofzeros

    nationofzeros Rookie

    May 14, 2006
    23
    dreamy doncaster
    Full Name:
    chris elliot
    Hopefully someone out there will have seen this one before...

    About an hour into a drive in my delightful 93 Mondial t yesterday, the ABS warning light came on - occasionally flickered on / off as I went over bumps in the road. BRAKE warning light didn't come on, and as expected in these circumstances brakes worked fine (although I didnt test the ABS!)

    Parked up, started again - the ABS light came on as always for first few seconds, went out, but came on again + stayed on after about 5 mins driving, as before

    Hopefully something simple - relay, connection, or similar as opposed to the ABS unit itself (here's hoping!)

    Any help gratefully received etc - thanks
     
  2. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
    72,740
    Vegas+Alabama
    Full Name:
    Mr. Sideways
  3. nationofzeros

    nationofzeros Rookie

    May 14, 2006
    23
    dreamy doncaster
    Full Name:
    chris elliot
    Thanks No Doubt for pointing me at a super resource. ABS code pulling this weekend for me !
     
  4. 4redude

    4redude Formula Junior

    Jan 13, 2005
    732
    Fungus Corner
    Full Name:
    Brian Keegan
    There is a Service Bulletin pertaining to the ECU for the ABS. It was an updated unit that sampled data from all four shock motors, not just one as before. The updated ECU has p/n 152008 on it and was installed on cars around Assy# 10425 onward IIRC.
     
  5. 4redude

    4redude Formula Junior

    Jan 13, 2005
    732
    Fungus Corner
    Full Name:
    Brian Keegan
    There is a Service Bulletin pertaining to the ECU for the ABS. It was an updated unit that sampled data from all four shock motors, not just one as before. The updated ECU has p/n 152008 on it and was installed on cars around Assy# 10425 onward IIRC.
     
  6. nationofzeros

    nationofzeros Rookie

    May 14, 2006
    23
    dreamy doncaster
    Full Name:
    chris elliot
    Ok thanks all - inserted 10A fuse into ABS unit empty holder, switched on ignition, waited and waited ... no ABS light flashing error codes at me or anything similar. Checked all the relay connections etc... sounds expensive?! ABS light still comes on (intermittently then permanently) during journeys although never at the start. I guess the next thing (on an empty wide road) is to see if the ABS actually does anything on hard braking...
     
  7. Mule

    Mule F1 Rookie
    Owner Rossa Subscribed

    Jun 25, 2003
    3,758
    Alaska
    Full Name:
    Mule
    Well, the light is "usually" triggered by low fluid, so you may want to add just a bit, since the sloshing on bumps may cause it.

    However, my 89 328 did the same thing and finally stayed on all the time. Brakes worked fine and the BRAKE FAILURE light never came on, just the ABS light. Turned out to be a valve that would slowly leak during driving lowering the fluid just enough to activate the light. Then at rest, the fluid level came back up to normal and the light went out. When it was started, the system charged, the valve leaked, the fluid dropped, the light came on.
     
  8. Ghibli Cup #11

    Ghibli Cup #11 Karting

    Jun 17, 2004
    85
    Bay Area
    Full Name:
    Noah
    The only reason the ABS light would come on if ABS was working was if there was a problem with the light. If you try a hard stop with the ABS light on, I would bet that you will end up flat spotting your tires. I would recommend reading the codes first and letting us know the results before risking that.
    The intermittent light is what I called a soft light, it resets itself when the failure is gone. Some failures cause hard lights that will only reset when you turn the key off and on again or when reset with the proper tool. The one failure that I can think of that might cause your symptoms is under/over voltage. The ABS unit will shut itself off if there is not enough power to operate the valves or motor, or so much that they will be fried. I think that the under voltage limit was around 7.5 volts. However you did not mention an alternator light so depending on what the voltage limits are for that this may or may not be the likely cause.
    The red brake light would not come on unless your car had EBD and ABS completely failed. You should read this thread for more info about ABS.
    http://ferrarichat.com/forum/showthread.php?t=143120
    Good Luck and keep us posted.
     

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