Bronco Forum - Full Size Ford Bronco Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
355 Posts
Discussion Starter #1
This is on a 94 Bronco with a 351w and e40d auto trans.

I really hate to ask about this, but here it goes. I've been doing a lot of reading on here trying to figure out what my VSS issue is. Like many others have talked about, I'm suffering from lack of speedo and the tranny is shifting hard. I also have an ABS light on. My odometer is there, but doesn't change. I threw a new sensor in the rear end because it was cheap and I didn't want to have to actually diag my problem. That didn't help.

I guess what I'm confused about is that I thought this sensor was for my speedo, transmission, and ABS, but some people have been telling me that it's for ABS only. Can someone clarify this for me.

I've checked fuses and stuff like that. How can I check my rear sensor to see if everything is working properly? Does it produce an AC voltage signal?

I have a couple of wiring diagrams and it looks like the wires from the rear sensor run from the sensor to the ABS module. I checked these wires for continuity and there are no breaks. Where does the signal go after the ABS module and what wires should I follow? (This is assuming that the rear sensor is for the speedo.)
 

·
Some assembly required!
Joined
·
5,402 Posts
It may not be the sensor, it may be the tone ring. Pull off the diff cover and look at it. You might be able to jack up the rear end, pull out the sensor and have someone rotate the rear wheels while you look down at the tone ring teeth through the sensor hole, but I've never tried it that way. It could also be a wiring fault somewhere.
 

·
Registered
Joined
·
11,108 Posts
I guess what I'm confused about is that I thought this sensor was for my speedo, transmission, and ABS, but some people have been telling me that it's for ABS only. Can someone clarify this for me.
Correct... on a 92+ the ABS sensor in the rear differential is for everything. The wires do to to the ABS module first, then from there they go to the PSOM, and then the PSOM outputs a corrected value to the EEC.

It was on previous years that it only fed ABS information, and the VSS information was taken at the transfer case.

Steve83's album is where I'd start... there is a wire (I can't remember the color for the life of me, and I literally just dealt with it) that goes from there to the PSOM... it's the one you'd have to jumper if you were removing the ABS module to keep your PSOM working.

But yeah, I'm with DB90... check the tone ring and look at the sensor for spacing. It's supposed to be extremely close. I think the spacing tolerances are listed in Steve's supermotors album as well.
 

·
Registered
Joined
·
16 Posts
I agree, go to stev83's post about the psom. I did the exact same thing you did, but then read steve83's psom entry. all I had to do was reset the speedo to accept the change that was made when swapping out the abs module. Works great now.
 

·
aka: kemicalburns
Joined
·
7,858 Posts
if the od is present but not moving and you have no speedo and the abs light is on then you ABS control module is acting up or bad. this unit is located under the washer fluid/rad over flow tank. do a search under my username i was able to test this theory by jumping 4 pins on the connector that plugs into the abs control module. once i jumped those pins i drove the truck and my speedo worked which pointed to the module being bad. I would almost guarantee this is your issue.

Here is the thread that discribes what pins need jumped on page 2
http://fullsizebronco.com/forum/showthread.php?t=102436&highlight=speedo+abs+module
 

·
Registered
Joined
·
355 Posts
Discussion Starter #6
Kemicalburns, I jumped those wires, and sure as shit, there's my speedo back. Shifts great too. Guess I'll be replacing the ABS module. Thanks for the help guys.
 

·
Registered
Joined
·
11,108 Posts
Kemicalburns, I jumped those wires, and sure as shit, there's my speedo back. Shifts great too. Guess I'll be eliminating the ABS module. Thanks for the help guys.
:thumbup
 

·
Registered
Joined
·
355 Posts
Discussion Starter #8
Yea that's actually what I did. I went to my friends junkyard and we pulled one out of a 94 Bronco. Put it in mine, and the problem still existed, so I just bypassed it.
 

·
aka: kemicalburns
Joined
·
7,858 Posts
Right on.
 
1 - 9 of 9 Posts
Top