ABS kicks in randomly, but no code

**Mindi51982** · 09-04-2009, 08:42 AM

So I have an interesting issue. Apparently it's common with my truck ('98 5.7L). The ABS will randomly kick in but it doesn't kick off a code. When I'm slowing down and almost completely stopped, the ABS kicks in. If I pump the break once, it goes back to normal. A guy that I work with has a plow truck that does that. It's been happening for years on that truck but hasn't caused any issues. I think they eventually just pulled the fuse for ABS and his issue went away. I guess I should try that. If it doesn't kick off a code, I have no idea what sensor would be bad. Anybody run into this issue and any advice as to how to fix it? It doesn't bother me now, but in the winter on icy roads it'll be a pain. Especially in Indiana...they don't salt the roads, leaving a very icy mess. Thanks!

**dano8928** · 09-04-2009, 09:08 AM

Yeahhhh youre not going to get a code. Most likely its your wheel bearings. I had the SAME thing happen last summer. I took the fuse out also for a while but im glad that i took it in the garage because we took the wheel off and the mechanic i was working on it with said he would have been suprised if my wheel stayed on for one more day. There was nothing left to the bearing. it came out in pieces. So start there. I dont know why it screws up the Anti Lock but it does. I almost hit a stone wall because of that haha. But like you said i pumped them once and they worked fine. Good luck and let me know if that works.

**Mindi51982** · 09-04-2009, 09:21 AM

Okay good thinking. We have an on-site mechanic so I'm going to see if he can look at the bearings for me. That's a good place to start. Thanks!

**dano8928** · 09-04-2009, 09:35 AM

No problem. I just got done looking at your mudding pictures with your ZR2. I had a 94 Blazer those things kick ass in the mud! haha let me know what you find out with your bearings.

**Mindi51982** · 09-10-2009, 11:27 AM

Had the mechanic at work look at it and he thinks it's something with the stater? He thinks it's like a disk with nodules on it that the sensor reads. If a couple nodules are rusted together, then the it can't sense to brake and the ABS will kick in. But he isn't sure if that's what it is called. It's either on the rotor or in the bearing. Anybody know?

**Jimmiee** · 09-10-2009, 04:06 PM

Originally Posted by Mindi51982

Had the mechanic at work look at it and he thinks it's something with the stater? He thinks it's like a disk with nodules on it that the sensor reads. If a couple nodules are rusted together, then the it can't sense to brake and the ABS will kick in. But he isn't sure if that's what it is called. It's either on the rotor or in the bearing. Anybody know?

It's called a reluctor or tone wheel. I believe you have found your problem. Can you clean it up so the sensor reads all the teeth? Even 1 tooth missing or a little mud can cause the ABS to kick in.

**Mindi51982** · 09-10-2009, 04:08 PM

Originally Posted by Jimmiee

It's called a reluctor or tone wheel. I believe you have found your problem. Can you clean it up so the sensor reads all the teeth? Even 1 tooth missing or a little mud can cause the ABS to kick in.

Okay. Can you help me with where this is actually located? Is it behind the rotor or is it in the wheel bearing? I have a '98

**Jimmiee** · 09-10-2009, 05:42 PM

Originally Posted by Mindi51982

Okay. Can you help me with where this is actually located? Is it behind the rotor or is it in the wheel bearing? I have a '98

Here's a picture. The sensor reads the teeth inside the rotor.

**2COR517** · 09-10-2009, 08:12 PM

A bad wheel speed sensor will cause the same problem. Your best bet is to get a good scanner on there and drive it. You need to see both wheel speeds and the rear driveshaft speed at once as you drive.

That will help isolate which wheel is giving you trouble. My ABS computer was bad, so I pulled the fuse. All better now. Except that stupid yellow ABS light on the dash LOL.

**2COR517** · 09-10-2009, 08:18 PM

Originally Posted by dano8928

Yeahhhh.....

Ahh, yeah. No. I'm gonna have to go ahead and disagree with you. I'm just not sure about that.

Are you an Office Space fan? I love Bill Lumberg!

Actually, I do disagree about the wheel bearings causing the issue. It's far more like that the stator and/or WSS was cleaned out in the process of changing your wheel bearing, in effect fixing the ABS issue at the same time.