96 chevy ABS update

at this stage dude, you're just wasting everybody's time. you've already been given a ton of excellent advice on what to do and how to do it. if you can't utilize that advice, either you need to give the vehicle to someone else who can, or get yourself educated to a point where you can. go to your local community college and sign up for one of the many auto tech courses that will teach you all this stuff.

as for the "I dont want to put alot of money in it" argument, that's bullshit. either you want to drive the vehicle or you don't. even if you dump a grand into fixing the problem, that's just a few months payments on a new vehicle, and unless you know there is something else catastrophically wrong, it will almost certainly outlast the payback period by a considerable margin and thus be totally cost effective.

I dont mind putting money at it, but I dont want to replace a sensor or other item that might not be the correct fix. I have listen to everyone's advice on here.

Can I use a resister at each of the speed sensors to check and see if it would fix the problem? WHat size resister would I need?

I wouldn't go back to this guy again for ANY reason. It's obvious he can not decipher simple trouble codes.

Since we now know that there are no qualified mechanics in your area, it looks like you are screwed.

It would be extremely foolish to modify any brake system unless of course you are a qualified engineer which clearly you are not.

Highly doubtful. You've got three open/erratic wheel speed sensors. Not surprising on a vehicle with over 300K miles on it.

"It fixed itself?" Should you even have a drivers license?

There are definitive test procedures for every failed part in your ABS system.

The sensors output an AC voltage signal, a substitute resistor will NOT do a damn thing other than confuse you more than you already are.

Can anyone direct me to what those procedures are? Like I said this is my daily driver and I would like to be able to repair myself. Also, I am having trouble finding the exact definition of those codes. One place on the internet said something also about an ABS pump failure for one of the codes and one just wheel speed senors.

I had my truck rear wheels off last night, where exactly is the rear wheel sensor? I did not see it anywhere in the hub.

stryped wrote in news: snipped-for-privacy@v18g2000vbc.googlegroups.com:

Have you considered

Probably on top of the diff.

Worthwhile ones; GM Service Information Mitchell On Demand AllData

If it says Haynes or Chilton on it, don't bother.

You don't have any pump related codes.

Those 5 codes, lacking as they may seem tell an awful lot about what is happening if one applies a little logic.

Left side of the transmission or left side of transfer case if 4X4. The rear wheel speed sensor for the ABS is the vehicle speed sensor, meaning it is connected to the VCM which then sends a speed signal on one wire to the BPMV (ABS controller). If your speedometer works, logic dictates that the speed sensor and wiring to the VCM is intact and the problem likely is in the wire between the VCM and BPMV.

You certainly haven't listed to a damn thing I've said in this thread.

At this point you might just want to take it to a competent brake shop.

--scott

What do you think it is? ALl three sensors bad? What is the BPMV?

I looked in my manual and the VCM is the vehicle control module. Where is this located? I assume I should be looking for the wire between the vcm and the ABS module under the hood? In my Hayes I believe it says that is a white wire but am having a problem figuring out where the vcm is.

A wheel bearing problem, a sensor problem, a wiring problem, a terminal problem, a cold solder joint somewhere, different size tires side to side. Doesn't matter what I "think" it is, I'm 400 miles away and my test leads are only long enough to reach from one end of a truck to the other...

What do the 13 letters after BPMV spell out?

Above the left front wheel house.

The white wire between the VCM and the BPMV only transfers the rear wheel speed sensor signal from the VCM to the BPMV, it correlates to just two of the stored codes (35 and 37) .

Which wire does the front and what shoudl I look for?

There is no wire that does the front.

What kind of voltage should I get supplyign each sensor, 12 volts with key on?

The sensors are little AC generators, THEY supply the voltage. The faster the wheel is turning, the higher the voltage, the faster the wheel is turning, the higher the frequency. (AC sinusoidal waveform)

You can do an ohm test at the BPMV for each sensor circuit (wire pair) and watch the ohm reading while you hand spin the wheel, reluctance will cause the ohm value to change as the tone ring move into and out of proximity with the sensor coil. Since the trouble codes indicate open circuits and missing signals, this should give some idea where the problem is.

As I remember it, my first GM ABS class was 16 hours, part textbook, part hands on, part lecture and theory.

You need a GOOD service manual with wiring diagrams, you need access to the TSBs that apply, you need a working knowledge of how the system operates electronically and hydraulically.

As I mentioned before, it is NOT necessary to bleed the ABS portion of the brakes when doing normal hydraulic service on your GM truck (this is straight from the GM service manual).

Have you resolved the low brake pedal issue yet?

rote:

I know, but a master cylinder replacement would cause the need to bleed the abs I believe. (I read that).

Acutally, the brake pedal is much better. What I ended up doing is adjusting the drums as well as install a new adjuster on one side. The adjusting made alot of difference on pedal feel.

I understand that ABS is complicated, that is why I am lookign for help! I like your idea of disconnucting the connector at the ABS module and checking each sensor at each wheel for ohm changes while spinning. I just need to find the correct wires to pair up. I have a diagram for in my Haynes manual but it is a little hard to follow. I have been looking online for a used GM service book but have found no luck.