Results 1 to 6 of 6

Thread: ABS scan at dealer vs. Pep boys

  1. #1

    Exclamation ABS scan at dealer vs. Pep boys

    I’ve got a 97 zj 4.0 and the ABS light is on, I cleaned all the abs sensors at the wheels and the light is still on. I was told the module was bad but before I replace that I should get the computer scanned to see if it is actually a sensor or bad module. My local dealer wants $82 to scan the computer even if I get the work done there. There is a dealer about 30min away that will scan for $60 and If it is a bad senor they will replace it for $120 total “60 parts, 60 labor”, they drop the scanning charge if you get the work done there. I would just replace the sensor myself but I might as well have them do it if its going to cost the same to buy it and do the work myself.

    My question is that if I can get my computer scanned at a local pep boys will it just show up bad abs module or will it be specific enough to tell me which sensor is bad if that’s the problem. I read somewhere that only the dealers scan will show an individual senor and not the whole module.

    Thanks
    Adam

  2. #2
    Registered
    Join Date
    Jul 2001
    Location
    NYC,NY, USA
    Posts
    1,858

    Default

    I believe that you can just unplug each wheel speed sensor and use a Digital Multimeter and test it yourself.

    If you let the dealer do it, there's gonna be a risk that the dealer won't be honest and tell you that more than one sensor is bad and may tell you more stuff is broken. The $120 bill may transform into a $1200 bill.
    1994 Hunter Green ZJ, 5.2L(Retired)
    2006 Commander Steel Blue Metallic 4.7 V8

  3. #3
    Registered ZJP's Avatar
    Join Date
    May 2001
    Location
    East Bay, CA, USA
    Posts
    353

    Default MultiMeter

    If you disconnect each one and run a meter on it you may find one that is totally different than the other 3...they will not all be exactly the same from my experience, but close...if they are all close then your issue may be somwhere else. Test all 4 and compare the results. You are looking for resistance in ohms. If you do a search you may find the specs...I don't remember the exact numbers you should see.

    It is a pain to get to the front plugs. 1 is under the master cyl and the other is under the washer fluid. The rears are under the drivers rear seat bottom...look for 2 ruberized wires that pop up from the floor board. Each sensor has 2 prongs in the connector.

    FYI sometimes even the dealer can misdiagnose ABS stuff. While you are there you can have them do a full ABS bleed on the system with the computer.
    2000 WJ 4.7 Limited.
    QDrive, Varilock, Five45RFE, 3" Magnaflow cat back.
    71k original miles and counting as of 4/22/2014.
    The long arms are gone IRO short arms.
    ACCOS all around. (Yes I welded in ZJ upper spring perches to install ACOS).
    285/65/18 on JK wheels.
    Addco Sways on both ends. HO cams if Chrysler ever makes them.

    Do I have to change my name to WJP now that I ran out of ZJs

    05 WK4.7 Laredo-sold
    96 ZJ 5.2 Limited-sold
    96 ZJ 4.0 Limited-sold
    93 ZJ 5.2 Limited-sold
    95 ZJ 5.2 Limited-sold twice
    And a hand full of CJs

  4. #4

    Default

    I did the multi meter test and came up with this.

    Front pass. .748
    front driver .757

    Red back .736 "didnt take the time to follow the wire to see which tire"
    Black back .737

    These all seem very close, does anybody know if any of these are out of spec, or if this means that it actully is the module that is bad like I was told by one mechanic. If it is the module, ive seen them for 97s on car-part.com from $45-150, Is this a hard thing to install, dosnt seem like it would be unless it gets into the hydrolic system. Also do you need to computer to rest the light or will I not be able to know if the replacment module works.

    Any ideas or help or expriences form those that have delt with this would be great.
    Thanks
    Adam

  5. #5
    Registered ZJP's Avatar
    Join Date
    May 2001
    Location
    East Bay, CA, USA
    Posts
    353

    Default Factory Manual was no help, but

    I dug out my 95 fsm and it has no info on the resistance. I think I remember my fronts being different than the backs.

    I would say pick up a front sensor and try replacing the highest number. I know we are only talking about .009 dif on the front, but they should be closer than that like the back numbers.

    I wish I had those numbers for you. If I get time tomorrow I will meter mine and reply back.

    When you pulled those sensors and cleaned everything did you gap the sensors? You MUST use a feeler gauge when you reinstall an existing sensor. Replacements have a cardboard spacer thing that wears off.

    Here are the specs from the 95 fsm: (quote)
    If original sensor is being installed or adjusted remove any remaining pieces of cardboard from the pickup face.
    Using a BRASS FEELER GAUGE set air gap to:
    0.92 - 1.45 mm (metric) or .036 - .057 in. (standard) depends on which feeler gauge you have.
    Torque bolt to 11 ft. lbs
    :pokin:
    2000 WJ 4.7 Limited.
    QDrive, Varilock, Five45RFE, 3" Magnaflow cat back.
    71k original miles and counting as of 4/22/2014.
    The long arms are gone IRO short arms.
    ACCOS all around. (Yes I welded in ZJ upper spring perches to install ACOS).
    285/65/18 on JK wheels.
    Addco Sways on both ends. HO cams if Chrysler ever makes them.

    Do I have to change my name to WJP now that I ran out of ZJs

    05 WK4.7 Laredo-sold
    96 ZJ 5.2 Limited-sold
    96 ZJ 4.0 Limited-sold
    93 ZJ 5.2 Limited-sold
    95 ZJ 5.2 Limited-sold twice
    And a hand full of CJs

  6. #6
    Registered ZJP's Avatar
    Join Date
    May 2001
    Location
    East Bay, CA, USA
    Posts
    353

    Default PS

    I am not sure what module you are talking about. The abs system has it's own ECU (computer), the hydro control unit (the thing with all the brake lines running into it that looks like a pump), the wheel speed sensors and the acceleration sensor (small black box thing mounted near the rear sensor plugs).

    If the ECU is what you are talking about it is easy to get to...flat silver box thing with a wiring harness thing plugged into it that is mounted near the fender in front of the abs pump stuff.

    Should probably disconnect the battery before you pull it...just incase.
    2000 WJ 4.7 Limited.
    QDrive, Varilock, Five45RFE, 3" Magnaflow cat back.
    71k original miles and counting as of 4/22/2014.
    The long arms are gone IRO short arms.
    ACCOS all around. (Yes I welded in ZJ upper spring perches to install ACOS).
    285/65/18 on JK wheels.
    Addco Sways on both ends. HO cams if Chrysler ever makes them.

    Do I have to change my name to WJP now that I ran out of ZJs

    05 WK4.7 Laredo-sold
    96 ZJ 5.2 Limited-sold
    96 ZJ 4.0 Limited-sold
    93 ZJ 5.2 Limited-sold
    95 ZJ 5.2 Limited-sold twice
    And a hand full of CJs

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Jeep Parts | Jeep Accessories | Trektop NX | Jeep Seat Covers | Jeep Wrangler | Jeep Wrangler Parts | Jeep Wrangler Accessories | Bestop | Jeep Tires | Jeep Stuff | Jeep Wrangler Tires | Jeep Wheels