1996 K1500 ABS activation HELP PLEASE!

Hey everyone!

I'm new to the forum so excuse me if I don't make complete sense all the time.

I own a 1996 Chevy K1500 stepside with a 5.7L V8 and have been having the same problems as a lot of other people out there with regard to ABS activation. Initially, the ABS only activated at low speeds but recently it has been activating any time I hit the brakes. As stopping correctly gets more and more difficult I am afraid of hitting something in front of me. On past cars that have had this problem, I just pulled the ABS fuse and the car ran like it didn't have ABS brakes - passed PA state inspection and everything was fine. But now I want to get the problem fixed right - especially because the ABS fuse on the K1500 is also the fuse for the cruise control, etc.

Can anyone walk me through the troubleshooting/repair of this problem??? I have all the tools necessary but not nearly enough between the ears to do the job without help so any info would be greatly appreciated.

So far, I know the sensors are located on the hub but that's about it. Does anyone have detailed pictures or anything on how to find out if they are the problem and then locate them exactly / clean them?

Thanks everyone in advance!!!

Hey everyone!

I'm new to the forum so excuse me if I don't make complete sense all the time.

I own a 1996 Chevy K1500 stepside with a 5.7L V8 and have been having the same problems as a lot of other people out there with regard to ABS activation. Initially, the ABS only activated at low speeds but recently it has been activating any time I hit the brakes. As stopping correctly gets more and more difficult I am afraid of hitting something in front of me. On past cars that have had this problem, I just pulled the ABS fuse and the car ran like it didn't have ABS brakes - passed PA state inspection and everything was fine. But now I want to get the problem fixed right - especially because the ABS fuse on the K1500 is also the fuse for the cruise control, etc.

Can anyone walk me through the troubleshooting/repair of this problem??? I have all the tools necessary but not nearly enough between the ears to do the job without help so any info would be greatly appreciated.

So far, I know the sensors are located on the hub but that's about it. Does anyone have detailed pictures or anything on how to find out if they are the problem and then locate them exactly / clean them?

Thanks everyone in advance!!!

My daughters Z-34 Lumina did this and the alternator was the culprit.

Thanks Mr. Smith for the info...

It's funny you mention the alternator because a few weeks ago I took my truck to a generator shop because the system seemed to be losing power on and off...the problem turned out to be a bad battery cable and terminal...but while I was there I had them check the alternator and that was perfectly fine. Go figure....maybe I should have it checked again.

Thanks Mr. Smith for the info...

It's funny you mention the alternator because a few weeks ago I took my truck to a generator shop because the system seemed to be losing power on and off...the problem turned out to be a bad battery cable and terminal...but while I was there I had them check the alternator and that was perfectly fine. Go figure....maybe I should have it checked again.
Unwarranted abs actuation is usually caused by a faulty wheel speed sensor, this should be scanned and driven with an abs capable scanner to look at codes and individual wheel speed inputs to determinen the problem.

Mine did this also. Its probably the whole wheel bearing/hub. The whole piece has the ABS sensor plug attached. Does your have about 100,000 or close to it.

My '98 Z71 did the same thing. Replaced master cylinder and one of the sensors and it didn't help. Turned out to be a bearing going bad and it was just enough to fool the sensor. Replaced the hub assembly and no problems since.

My '98 Z71 did the same thing. Replaced master cylinder and one of the sensors and it didn't help. Turned out to be a bearing going bad and it was just enough to fool the sensor. Replaced the hub assembly and no problems since.

like i said

Unwarranted abs actuation is usually caused by a faulty wheel speed sensor, this should be scanned and driven with an abs capable scanner to look at codes and individual wheel speed inputs to determinen the problem.
I agree! Generaly its a bad wheel speed sensor that as your stopping it missreads the wheel speed telling the system that wheel is going slower than the rest and then on come the anti-locks. However you do need to have the right scanner to physically see the problem If you can have it scanned they are easy to replace.

Thanks for the help.

Since I don't have a scanner I was thinking of people who could scan it for me. Advance Auto Parts will scan the OBD system for me for free...is this what you're talking about??? If not, can someone explain how I can diagnose the problem myself?

Advance will not do this, you will need to seek a gaarage with an abs capable scanner, you could check the resistances with an ohmeter, usually around 1200-1600 ohms depending on temp, but it still could be bad even with this check

Thanks for the advice. I'm glad you told me...I guess I don't know as much about this problem as I thought.

Can you explain exactly what I need to check with the Ohm meter (where to place the leads)? I'm in 20 degree weather with heavy snow now...I don't know if that will affect the reading or not. Also, I'm not sure if this will help, but every time the ABS activates, the system seems to be losing power...the headlights dim to about half brightness. Does that mean anything to you?

If the readings are outside of the normal range you mentioned, what does that indicate?

Thanks in advance!!!

Can anybody help me?

Are the speed sensors located on the front wheels only...The little white boxes behind the hub assembly???

Anyone know if these are the ones:

http://www.partsamerica.com/ProductDetail.aspx?mfrcode=RAY&mfrpartnumber=ABS530581&parttype=1061&ptset=A

???

The rear has sensors also. The leads connect to the sensor contacts inside the connector to each speed sensor. Remember my 1st post .

The rear has sensors also. The leads connect to the sensor contacts inside the connector to each speed sensor. Remember my 1st post .

Ok yeah, I gotcha. I guess I just couldn't find the parts online. You don't happen to know exactly how to diagnose and/or fix each wheel do ya?

I got lucky with this problem on a '95 Sierra. Thoroughly cleaned the sensors and pickups on the front wheels with rubbing alcohol and the dash lights went out. I think it takes a few startups and drives for the system to reset. This is a common problem.

Check out these websites for more than you ever wanted to know about ABS and GM brakes.

My personal experience with an ABS light turned out to be a faulty passenger side ABS sensor. The picture from Advance Auto is very close to correct, the only difference from the picture would be the mounting bracket for the wire so that it does not get caught in suspension movement. I personally tried getting that sensor every way that I possibly could without paying $100. Timken is the OEM supplier to GM and boy are they proud of them! Siemens(Autozone, after searching through catalogs) also makes them, but for the same price. Hell for that price you might as well go ahead and buy the whole bearing/sensor assembly as one unit. I can't remember if I had to remove the whole assembly anyway just to access the allen head screw that holds the sensor to the hub. In any case, good luck. A word of warning though, if you do end up having to remove the hub assembly just to access the sensor, you will ABSOLUTELY NEED an impact gun of enough strength to bust the 3 bolts out of the spindle. Usually they are somewhat rusted into place, use PBlaster liberally, and wait overnight. If your doing this outside, the colder it is, the tougher it gets.

Hope this helps -Chris 96 Z71 5.7L All stock :wave:

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Wow...that is a TON of info...and very helpful!!!

Thanks a lot...I can't wait to get started so I can get this problem fixed...the constant ABS activation is driving me nuts...especially when it's 5 degrees out and the chances of sliding are pretty high.

Thanks everyone for the help...

One sensor cleaned....four to go.

I hope I find the problem sensor before I get to the last one...getting to the sensors takes a lot of time.

Cleaned both front sensors and am down to 3 (including the Vehicle Speed sensor) to clean.

I thought the rear speed sensors were behind the primary brake shoe but I don't see any wiring going to the drum assembly...are they located somewhere else or is it posssible that there are only 2 sensors (the front ones)???

Also, there is a hose going into the rear axle...anyone know if that is the vehicle speed sensor?

Found out after tearing the truck apart a few times that one of the sensors (driver's side) had broken off in the bore...I'm pretty sure it was from me having to pry the sensor out a little even though I tried to be as gentle as possible. Whether or not that sensor was causing the original problem, I need to replace it so that water doesn't leak down into the CV....

I know from the earlier responses that these sensors are hard to find for under $100 (my dealer wants $140 and Advance, etc. want ~$100)

Can anyone help me find one used??? I've tried all kinds of websites but the best I can find is $65...At this point I would even settle for a nonworking sensor just to seal the bore for $20 just to seal the bore up until I can get around to buying a used sensor later. I just need to get my truck back on the road.

Thanks for the help!!!