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-   -   Anti-Lock Brakes (http://www.jeepforum.com/forum/f13/anti-lock-brakes-716970/)

steve L. 03-06-2009 03:58 PM

Anti-Lock Brakes
 
Hey you guys. My '97 ZJ has anti-lock brakes, but they dont work. Whats even weider is that the light on the dash isnt lit up either. Why is that? I have tested em several times, and I really put them to the test with all that snow we just got over here in Jersey. How would I go about this problem? Is it an expensive fix? or is it something I can fix on my own?

thanks you guys.

Turbonut 03-06-2009 06:30 PM

Power to the ABS unit? I believe it should run through a system self check when the Jeep is started to be driven. Probably somebody disconnected the ABS bulb, or simply removed it from the dash.

steve L. 03-06-2009 07:15 PM

aww yea. I had my entire dash torn apart today doing other things, and it never occured to me to see if the bulb went out or if someone pulled the plug. And if someone pulled the plug, that means the dealer sold it to me that way...not knowing of course, and the previous owner must have pulled it so he would be able to sell it..
Now how would I go about fixing all of this? both the bulb and the anti-lock brakes?

steve L. 03-06-2009 09:10 PM

??anyone??

_Kyle_ 03-06-2009 09:37 PM

You'd have to go to a brake shop to have them read your ABS codes, if you have any. They would be able to tell you whats wrong.

My ABS lights been on in my 96 for over 3 years and its on in my 97...I prefer to drive without ABS.

steve L. 03-06-2009 09:42 PM

well I hear that the ABS are really sensitive on our jeeps. is this true? This being my first vehicle n'll, I never experianced them goin off on me.

so what your saying is that if i do get them fixed...I most likely wont be able to do them on my own, and its gonna be expensive...

compcrasher86 03-07-2009 01:02 AM

yup yup yup ABS doesnt work on my jeep either. 97 ZJ and its supposed to have ABS but whats different is my light is on. Everything looks fine to me, I checked all the fuses, connectors, and everything. I want ABS just cause, well, idk if its there I want it to at least work! I connected my OBD scanner and it found a rogue code of B001 or something. Google searching said it meant no power to the ABS or something but I couldnt find a problem after testing the wires. I wonder who checks ABS codes around here?

you can follow my thread if you want and I'll keep ya updated:
http://www.jeepforum.com/forum/f13/jeep-zj-abs-light-abs-not-functional-632283/

And trust me, I'm positive mine dont work hehehe :D

_Kyle_ 03-07-2009 07:10 AM

Your regular OBDII reader won't read ABS codes. It takes a special reader to do it.

rm2001wj 03-07-2009 10:40 AM

Quote:

Originally Posted by steve L. (Post 6738850)
Hey you guys. My '97 ZJ has anti-lock brakes, but they dont work. Whats even weider is that the light on the dash isnt lit up either. Why is that? I have tested em several times, and I really put them to the test with all that snow we just got over here in Jersey. How would I go about this problem? Is it an expensive fix? or is it something I can fix on my own?

thanks you guys.

You may have the wrong idea about how the ABS work. If a wheel is locked by the brakes while another is not, the ABS will very briefly release the locked wheel, and then try to lock it again. This locking and releasing goes on until both wheels turn at the same speed or until both wheels are locked. Ice and show are not the best conditions for testing because it is too easy to lock all the wheels. Instead, find some clean dry pavement and slam on the brakes. If the brakes are strong enough to lock a wheel, the ABS will do it's thing, assuming that it is working. With oversized tires on a lifted Jeep, the brakes might not be strong enough to lock any wheel, and you can't tell if it is working or not.

steve L. 03-07-2009 12:05 PM

Quote:

Originally Posted by rm2001wj (Post 6743251)
You may have the wrong idea about how the ABS work. If a wheel is locked by the brakes while another is not, the ABS will very briefly release the locked wheel, and then try to lock it again. This locking and releasing goes on until both wheels turn at the same speed or until both wheels are locked. Ice and show are not the best conditions for testing because it is too easy to lock all the wheels. Instead, find some clean dry pavement and slam on the brakes. If the brakes are strong enough to lock a wheel, the ABS will do it's thing, assuming that it is working. With oversized tires on a lifted Jeep, the brakes might not be strong enough to lock any wheel, and you can't tell if it is working or not.

I have tested them on dry pavement, along with on wet pavement after it rained. I always skid forward and my back end fish tails. I have never once felt them go off. I dont have oversized wheels either, I only have 235/75/15 tires, no lift.

rm2001wj 03-07-2009 03:33 PM

It seemed to me you were using the response of your ZJ in ice and snow to decide that the ABS is not working. Slippery surfaces are simply not what you need to test ABS, because braking action will tend to lock all the wheels and the ABS just can't help that situation. ABS needs one wheel turning and another not turning in order to know it has to do something. On dry pavement, if you are able to lock any wheels (typically one for the front wheels since they have the strongest braking action) so that you can hear the tire screeching and the ABS doesn't react, then the ABS has failed. If the ABS does engage under those conditions, you will definitely notice it. Also, I repeat, brakes must be strong enough to lock lock up one or more wheels on dry pavement in order to test the ABS when driving.

Are you saying that on dry pavement one of the front wheels locked (you heard the tire screeching) and the rear end swung out? :confused:

steve L. 03-07-2009 03:58 PM

No when it was icy / snowy on the ground, in an open area I went about 20-25mph and slammed on my brakes. If the ABS was working, the brake pedal should have pulsated in a strong vibrating motion but it didnt. Nothing happened, it felt like I was was braking on dry pavement except that since it was slippery, so I fish-tailed and went sideways. Again - no vibrating in the brakes.

My brother had a ZJ in the same condition, his went off, mine didnt.

I tried turning the key to "on" and noticed the ABS light doesn't light up on startup. I'm wondering if someone before me pulled the bulb. I'll have to check next time I have the dash apart.

Also, I did the key trick and got error code 55...is that related?

compcrasher86 03-08-2009 10:55 AM

error code 55 is not related, it just signals the end of code reading

And if you wanna pull off your instrument panel to check if the bulb was pulled its pretty easy. First, pull off the woodgrain/plastic trim around the headlamp switch and around the climate/rear wipers switches. Theres no screws, just clips that pop out. I always use my hands, others swear by a plastic putty knife. Then look at the plastic that covers the edges of the instrument panel, and the air vents are attached to. There should be five? screws on the top of it under the overhang and I think its four screws under where the trim pieces with spring clips were attached. Unscrew all of these with phillips head screw driver. Then tilt the steering wheel all the way down and start at the top of the plastic and sort of finnessing it out (like pull it down by the edge and out) then if all screws are remove it'll come right out in one piece. Then look at the instrument panel and undo the four screw on the left and right sides. It will just pop out, there is no wiring harnesses, it just seats itself into a plug when it is put in. Then look on the back and look where it says ABS at the bottom. If the bulb is there, check and make sure its not blown out

compcrasher86 03-08-2009 10:58 AM

Quote:

Originally Posted by _Kyle_ (Post 6742549)
Your regular OBDII reader won't read ABS codes. It takes a special reader to do it.

I have the ELM 327 Interface, the one that you can hook up to your laptop and read all the codes, get live gauge and sensor data, graph stuff, clear codes, etc. Its not the ordinary plastic box with a 1 line screen your thinking about. I still trust you though, it wouldnt make sense to me to pull that kind of info without a special reader. I gotta find somewhere that will pull the codes for free for me cause no doubt the dealer will charge $100+ for a scan, calling it "diagnostics+labor"

steve L. 03-08-2009 11:06 AM

Eerror code 55 is not related, it just signals the end of code reading-Compcrasher86

oh alright sweet. thanks man. I think someone pulled the bulb on me, bc when I turn the key to the on position, the ABS light doesnt even show. Im leaving to go back to school today, so when I come home again in about 2 weeks, Ill take my dash apart and check it out.


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