I am having some troubles with my VSS in the rear end of my 95 F250. I took it out the other day to see if it was dirty and would fix a problem and when I put it back in and test drove the truck, the ABS light stays on and the speedo doens't work. So I think I broke the VSS in this process.

My questions are:

When I remove the VSS from the rear end, what should I see in the hole? Should I be able to see the gears or not?

Assuming something got broke off in the hole, what would be the best way to get it out? Would removing the differential cover allow me to push it out from the inside or can I not get that far?

I was able to cross reference the part number on the VSS with a part that I can replce it with but it will be a few days until that part gets here so I can't compare the two just yet. I am hoping to get in there this weekend and see what I can do.

Thanks.

 

look at the VSS if theres nothing broke off the end that goes into the diff dont worry about it if there is pull the cover off and find it and get it out cause it might cause damage to the gears...did you try clearing the codes im not sure if that would help the abs light but it might, just remove the negative battery terminal then put it back on go for a good test drive get it up to highway speed and all that so the baseline of all the sensors gets reset...read around FFI for a while it helped me alot heres the link Ford Fuel Injection

they have a writeup of the VSS too check that out cause it might not be the VSS itself

 

Do NOT do what 9.ford.5 said.

The PCM Computer and the VSS, Speedometer, and the ABS are two different systems.

Do not unhook the battery as this will only cause codes to be set in the CM of the computer.
All manuals say do not unhook the battery as it will cause more problems then if will fix. More than likely it will run worse after you do this and making fixing other problems harder.
Always use a 9V Battery plugged into the lighter receptacle whenever you unhook the battery to maintain the computer memory.

When you replace a sensor if its out put is in the ballpark range the the Computer will use this valve, if it is outside the ballpark range the computer will ignore this valve and use the last known good valve it has stored. If it does not have a good valve from the sensor or one stored in memory then it will use the substitute value it has in non volatile memory.
Note that this does apply to all sensors just the ones that can be substituted.

 

Others have reported breaking the VSS while removing it. The VSS is a magnet switch and almost never goes bad.

 

still don't have any idea if this broke off when I removed it because I don't know what an intact factory one should look like.

What I have is the whole part that came out of the rear end and there is a magnet in the middle. This magnet is loose and just falls out in my hand. There is a small washer in there also and there seems to be a cup in the hole where this came out of so I can't see any gears. I am not sure if that cup is part of the VSS or not because I don't know what an intact one looks like from Ford.

But it seems that no matter if I put it in with the washer on the bottom or top of the magnet, it doens't seem to work.

I haven't found this part referenced in my Haynes manual so I am not sure how to test it.

An interesting thing about the part I removed...I called up the parts place and gave them the Ford part number from the part I removed. It came back as a part that looks like I can use. I got their part number (FF1024) and went' to partsamerica.com and put that in, it came up and the interesting thing is that the web site said this part was mostly for Econoline vehicles. The part number that I found which most resembled that part is S8319 and this part is for F series trucks. I just might get both and try the one for my truck and if that doens't work I will use the other and return what I don't use.

 

Part of the VSS is still in the hole.
Here is a VSS sensor I just removed from a 2001 F-150 8.8".
It should be the same.
All of my 95 VSS sensors are still in the rear ends and I have taken them out yet.





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OK!!! that was what I needed to know...thx.

I took a pic of mine, it is here: ImageShack - Hosting :: dscn2377customzw7.jpg

I pulled out the magnet a little so you could see it, washer is on the end of the magnet. Don't have anything here to measure with.

Any suggestions about getting out the stuck part from the rear end? Should I mess with it somehow through the hole it came out of or should I remove the cover to the rear end?

 

I am not sure how easy it is to get to the area if you take the back cover off.
Another member broke one off but did not tell how he got it out.
I would try from the out side first but do not push down very hard because of the tone ring under it.
If you take the cover off do not pry against the tone ring.
If you have over 50,000 miles on the oil then go ahead and pull the cover as you need to change the oil anyway.
Make sure you let us know what you do and how it comes out.
Good Luck

 

"The ECC has programming that admits not all sensors are created equal. Once you have installed a new sensor you then re-attach the battery, you disconnected it right? You should have, and not just to protect against arcs, the EEC’s Keep-Alive memory stores the sensor irregularities. Sensors are not all manufactured the same; there is a 15% tolerance from one sensor to the next one rolling off the assembly line. Once you re-connect the battery the KAM reads all the sensor baselines and stores these as “normal.”

"If the sensor (over time) starts to loss its sensitivity, the EEC will catch on (from its original memory) and begin to compensate for this. As the sensor ages and it’s readings get worse a fault code will be stored in the KAM memory. When trouble shooting a problem, always check for codes prior to disconnecting the battery, which erases the codes stored in the KAM memory. Then any codes next time will be after your last repair."

therefore before you replace the sensor disconnect the battery so when ur done and the battery is reattached the EEC will reset the baseline reading of the sensor and your previous codes will be cleared. any local mechanic will agree

BTW site is Ford Fuel Injection Sensors

 

That's all true, but there really isn't a baseline with a pulsed wheel speed pickup. It either signals each tooth or it doesn't -- there's no adaptation.

 

mother effer, this was a beast to get out.

ImageShack - Hosting :: dscn2383custombg2.jpg

But I got it.

One thing to be aware of if you are in this situation, the part that is left in the rear end should be removed before the vehicle is driven. It could slip down further and cause problems with the gears in the rear end.

 

Is every thing OK now?

 

Seems to me when the ABS sys. went south on me awhile back on my 87', there was brake sys. test terminal under the dash/drivers side like the one under the hood for the EEC, the brake test is triggered the same way (Paper clip jumper). I think shuting the key off during test mode clears the brake error codes.

 

The VSS that Subford pictured fits better than the one you removed. I replaced mine 2 times and the first one I bought was like the broken one you have pictured.

Right after I replaced it I tried to go for a test drive and heard clicking when I backed up. So, I pulled back forward and parked it and removed the VSS. Well it was dented and broken. So, I took it back and got one like Subford's. My original one looked like that as well. The Wells brand one from Autozone looks the same as the one Subford pictured.

 

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