Hi All, New here
I had my Speedo on my ranger go dead. It would work intermittantly. I replaced the VSS in the rear differential and it worked briefly, but died again. Any ideas on what to do now? Is there another sensor I need to replace? It works for approximately 12 miles then dies again.
Thanks!

 

if you have the same truck as me I think you have the vss/abs sensor in the diff and that's it. I guess there is a chance you have a loose wire somewhere, however my guess is you might have got a bad sensor. I put one in about a year ago it worked for maybe 3 months. I then racked my brain trying to find out what it could be becuase i assumed the new part was fine. about 6 months ago i went and bought another one at autozone for $20 ( the first one I bought at autozone also)and it has been fine ever since. if it happens again I am going to see if motorcraft makes one . I learned in my investgation that the sensor is very sensitive to how it sits on the differential if it is off a little it can cause an issue. you have to clean the top of the diff off where the sensor sits. put some oil on the oring before you istall it. make sure it sits perfectly in its spot. my symtoms where a erratic speedo, clicking from under the dash and the abs liht would come on and off. let us know what happens.
p.s. obviosly you could check fro ower back at the sensor and make sure your fuses are fine etc. but i think it is the vass/abs sensor....... if you have an auto tranny the bad sensor could cause shifting issues

pps. I looked on rockauto and they have a sensor that looks like the one that would go on your tranny but I dont think you have one of those I think it is just the one in the diff. lets us know if you have manual or autoa nd 2wd or 4wd

 

thanks powersmoked,
I have the manual transmission and 4x4. The speedo works for the first 5-10 minutes of driving then stops - with the new sensor put in - and that's what it did before I replaced the old one.

 

mine was the opposite it would not work until 10mph.

 

A quick look at the speedometer circuit wiring diagram will tell you if you also have a VSS plugged into the side of the trans.

FWIW, my 97 Explorer does have a second VSS in the drivers side of the trans.

You can probably find the wiring diaram at autozone.com

 

I am pretty sure that 98,99 &2000 have just the one in the diff that feeds info to the pcm abs and speedo.

 

Well in that case I wonder how the cruise control is working?

 

I think in the 98-00 they went to the single sensor in the rear axle. I have seen many people posting that "some" of the things governed by this sensor will go out or not work properly, but its not always the same exact symptoms from person to person.

 

So I think what u are saying is that the one vss/abs sensor in the diff can go BAD and cause all kinds of different problems for each truck. You are saying the each truck will have consistent issues for one truck and different consistent issues for another truck. At the end both of the trucks issues are caused by the same defective sensor in the diff. I think that is what you are saying and if it is. I agree with you.

 

Welcome to FTE.

Have a read through this post & if that isn't it, maybe read through the remainder of the thread on some more things to look for & let us know what you find.
Ford Truck Enthusiasts Forums - View Single Post - Possible speed sensor problem Paw Paw please help

 

Yes, First before proceeding read my signature! But this is from reading the forums (and having one go bad myself). Seems like they fail and cause different symptoms. Sometimes speedo (no speedo, failed reading low speed, failed reading high speed), sometimes transmission shifting issues, sometimes a warning light, sometimes not, sometimes, and others. Seems to change from truck to truck and sensor to sensor. I have read people who cleaned the sensor (its a magnet and gets metal on it).

AND there have been folks on here that had them fail either right away or pretty fast.

Someone else back me up if thats what they have read too.

BUT it could be a wiring issue too as that can cause the same symptoms.

 

Thanks for all the replies. To add a bit more info; There is no warning light in the dash that is on, no check engine light, the cruise works fine and it's a manual transmission, so there are no problems with shifting. I pulled it out again today, and put it back in and it worked for 40 miles and then died again - no fluctuating of the needle before it stops - just goes from 70 to 0. I'm wondering if there is by chance metal shavings of some sort getting stuck to the magnet which is causing it not to "Pulse". I know I have not changed the fluid in the rear differential since I have had the vehicle which has been 7 years. Could that be a culprit for it? I also put super lube on the connector and I'm not sure if that made a difference or not.

 

I had been thinking the same thing about the diff fluid. one thing i did right before i changed the sensor the second time is i checked the fluid and it needed about a quart. what sensor does the cruise work off of. I am curious about that

 

I'm not sure which sensor the cruise runs off of. I will have to do some checking on that also.

 

The cruise control also uses the rear ABS speed sensors PID output to the computer, as does an auto tranny & speed-o & the ABS system.

Let think about this some more, seeing as how the speed-o will work for 40 miles or so after the speed sensor & it's electrical connector is messed with, so it seems to me it's electrical connector, wiring, or the new speed sensor should be at the top of your suspect list.

In the link I posted above, a member found his covering wire loom had cracked about 2 feet from the differential & that break had chafed & worn through the wires insulation such that they were making intermitent shorting contact, as air flow & vibrations moved them, so check your wiring & covering wire looms condition carefully, as well as the condition of the speed sensors electrical connector pins or sockets & the wiring as it goes into the connector.

Look for bent pins, spread sockets, corrosion, bulging insulation where the wire strands may have broken undeneath from flexing, cut insulation, ect.

If all that checks ok, then maybe suspect the new speed sensor.

More thoughts for pondeing.
Let us know what you find.