ABS malfunction after collision with a car

Discussion in 'Maintenance' started by guga50, Jul 16, 2013.

  1. guga50

    guga50 New Member

    Joined:
    Jul 16, 2013
    Messages:
    6
    Likes Received:
    0
    A car hit me from the right side in my leg and in a rear brake pedal. After a collision the pedal was deformed a little bit. So I considered that a damage is not worth to mess around, straighten out brake pedal and went off. But an ABS light was on all the time. When I tried a rear brake hard enough a rear wheel blocked.
    After checking errors I've got two codes "54" (Rear power unit malfunction/air bleeding incompletion/rear brake caliper piston malfunction) and "21" (battery voltage malfunction/blown fuse). I checked ABS fuse (20A) it's OK. When I remove it ABS light not showing errors and when I place it back diagnostic codes are showed fine.
    I tried to go to an official dealer but they announced price as if I asked them to built the large hadron collider. So I'm on my own with this situation. But I don't know from what should I start trying to determine the problem.
    Frankly speaking I'm not using the rear brake at all. But I'm not sure whether a front side of ABS system is working as usual or not. I tried to brake hard several times and it seems that front ABS works, but I'm not sure. Maybe it wasn't hard enough and to insist on locking front tire is not good idea I think. (kinda scary for me...)
    So the questions.
    Is a front ABS is still working with these codes?
    Is it possible to disassemble the rear unit and try to repair it?

    Tomorrow gonna try to bleed brakes. Seems to me like a reasonable starting point...
    Any ideas?
     
    #1 guga50, Jul 16, 2013
    Last edited: Jul 16, 2013
  2. Ian E

    Ian E Active Member

    Joined:
    Mar 2, 2013
    Messages:
    1,459
    Likes Received:
    472
  3. Slick

    Slick Elite Member

    Joined:
    Nov 11, 2012
    Messages:
    2,491
    Likes Received:
    1,242
    Welcome mate, bad news about your incident but at least you are OK

    Firstly I would assume if your light is on that ABS is not working front and rear. I had a 5-2 Front power unit malfunction/air bleeding incompletion/front brake caliper piston malfunction but this allowed me to lock the rears. This was fixed by a full bleed.

    Before you bleed check the obvious like a sensor hasn't been knocked or the wires are not damaged. Also check the rear MC hasn't suffered a knock.

    Regarding bleeding, it is quite easy. The first time takes a while as you are familiarising yourself on which panels to remove to expose bleed nipples and the ABS diagnostic port. I've done it a few times now and can easily do it in less than an hour. Just take your time and read the instruction carefully.
     
  4. vvtr

    vvtr New Member

    Joined:
    May 27, 2013
    Messages:
    200
    Likes Received:
    98
    :D AHAHAH I LIKE THAT :d

    GOOD LUCK AND LET US NOW HOW IT GOES AFTER THE BLEED.
    is it possible the master cylinder piston was damaged / bent in the crash?
    is the rear brake losing fluid at all from the master cylinder?
    i'm guessing as i dont have abs on mine, but surely it would detect a pressure loss?
     
  5. guga50

    guga50 New Member

    Joined:
    Jul 16, 2013
    Messages:
    6
    Likes Received:
    0
    I'm afraid that pressure sensors inside an abs valve assy could be damaged by a pressure impact. It also can explain these fault codes. But anyway let's begin with bleeding.
     
  6. Swiss T

    Swiss T Active Member

    Joined:
    Feb 22, 2012
    Messages:
    680
    Likes Received:
    346
    I think the best advise has been given; good luck.

    Is this damage not covered by the other party's insurance; they hit you yes?
     
  7. guga50

    guga50 New Member

    Joined:
    Jul 16, 2013
    Messages:
    6
    Likes Received:
    0
    Not working after bleeding. Can't figure out how to clear errors from ABS.
     
  8. Slick

    Slick Elite Member

    Joined:
    Nov 11, 2012
    Messages:
    2,491
    Likes Received:
    1,242
    With the jumper disconnected turn the ignition off and on 5 times each time waiting for the starting procedure to complete


    from bleeding manual

    Untitled.jpg
     
  9. guga50

    guga50 New Member

    Joined:
    Jul 16, 2013
    Messages:
    6
    Likes Received:
    0
    I have done it. Now Error codes gone. ABS still doesn't work. When I try to check errors I have just continuous blinking.
    Here is a video ABS Test - YouTube First time (from start to 1 minute) in DTC mode with jumper shorted, and second time (from 1 minute till the end) in normal mode.
     
  10. Slick

    Slick Elite Member

    Joined:
    Nov 11, 2012
    Messages:
    2,491
    Likes Received:
    1,242
    I guess the light flashes once you ride off, but when you check the codes there nothing but blinking?
     
  11. guga50

    guga50 New Member

    Joined:
    Jul 16, 2013
    Messages:
    6
    Likes Received:
    0
    The abs light is on all the time while riding. when checking errors there are no error codes, just blinking. Tried to remove the main abs fuse and check errors - the light is on all the time. While bleeding all actuators and motors were working fine, system was working like it stated in the manual. For example before motor activation a brake pedal become very stiff and then the motor activated and just after that the system "release" the pedal. Just cant understand. After errors reset I went for a ride for at least one hour. I though that error codes should reappear. But I've got what you can see in the video.
    Anybody knows are there any other fuses for ABS except the "main abs" in a fuse box?
     
    #11 guga50, Jul 20, 2013
    Last edited: Jul 20, 2013
  12. guga50

    guga50 New Member

    Joined:
    Jul 16, 2013
    Messages:
    6
    Likes Received:
    0
    By the way I have managed to repair the valve unit. (just forgot to post here). The problem was one of two pressure sensors as I had expected. I cracked the unit with a chisel, unsoldered wires from pins and wired connections out of the box. Then I installed the unit to the moto, bleeded it and measured signals from pressure sensors. I had not any schemes except of some picture from honda C-ABS advertisment. So i figured out the function of each wire and saw that one sensor was broken. I connected both channels to a good one and ABS is working now. Now it looks like this.
    Actually gonna buy a used one from USA for just 250 bucks cos it's trivial that two duplicating sensors were installed not just for lulz.
     
    #12 guga50, Nov 3, 2013
    Last edited: Nov 3, 2013
  13. sinewave

    sinewave God Like

    Joined:
    Jan 12, 2013
    Messages:
    8,134
    Likes Received:
    4,614

Share This Page