1999 Ford Taurus - Speedometer drops to zero and trouble shifting

I have a 1999 Ford Taurus.

It runs fine for a while then all of a sudden the speedomoter drops to zero and the car has trouble shifting from low gear.

I first noticed this problem in Staten Island, NY traffic. Entering Staten Island the traffic always comes to a virtual stand still. While crawling, the speedomoter all of a sudden shut off. The car continued on fine however, I was even able to drive at full speed and after a little while of full speed driving, the speedometer even showed up again!

But the problem I guess has worsened with lack of attention, and now the speedometer shutoff is coupled with a difficulty or inability of the car to progress from low gear and therefore a cap on my speed (20 mph maybe? I don't want to over rev the engine, thankfully when this has happened I'm usually within coasting distance of my destination as it takes a little while before it becomes a problem. If the car sits for an hour or so, it will start back fine with the speedometer on and re-do the same process of eventually blanking out again and not shifting.

Anyone know what the problem is, and if so, how much would it cost to fix? thanks!

Is your check engine light on?

It sounds like you have a problem with the vehicle speed sensor. You can probably find details on location and how to replace by searching this forum for keyword "VSS."

-Rod

Is your check engine light on?

No.

Rod, Thats what I think as well, and to be honest with you I'm not going to pay $95 to bring it to ford so they can confirm it for me only to tell me that they are going to charge me another $200 to replace it when Autozone is selling a replacement part for $15.99?!

Does this sound right?

I ran a search and found how to locate it but to be honest with you I just went outside and couldn't find it. does anyone have a diagram that could help me? Would it help if i took a picture of the area of interest and maybe someone could circle where i should be looking for it?

Thanks

Though it should be noted, I also seem to be having a likely unrelated problem? Where turning the A/C on results in a bit of what feels like a grind on the motor resulting in the instinctual turning off of the A/C to prevent the car from stalling :)

Though it should be noted, I also seem to be having a likely unrelated problem? Where turning the A/C on results in a bit of what feels like a grind on the motor resulting in the instinctual turning off of the A/C to prevent the car from stalling :)

What do you mean by "a grind on the motor?" If you just mean that it loads the engine and the engine speed drops, that sounds like an issue with the Idle Air Control (IAC) servo. This is sometimes referred to as an Idle Speed Control as well.

-Rod

The vehicle speed sensor will have two wires going to it, a Pink/Orange and a gray/black wire. It is located on the transaxle in the rear center location of the engine compartment. Since you didn't mention which engine you have, I'm trusting it's the 12V Vulcan engine.

-Rod

The vehicle speed sensor will have two wires going to it, a Pink/Orange and a gray/black wire. It is located on the transaxle in the rear center location of the engine compartment. Since you didn't mention which engine you have, I'm trusting it's the 12V Vulcan engine.

-Rod
So I went to Autozone and he said what I need to know is not necessarily the engine but the transmission type?

He said theres two types for a 1999 Taurus, a "AXN" and "AXS"

So I crawled under the car, and sure enough, the only thing I could find was the letters "AXOD"

I took a bunch of pictures and I'm about to "Count the Bolts" to try to pinpoint which one it is. Incredible that I'm sitting here counting bolts on a photograph because theres no way to figure out which type of transmission I have otherwise. I even pulled up the VIN and the only thing it listed was the generic type not the specific name. Apparently there is a different speed sensor depending on the transmission type.


And when I count the bolts I keep getting "16"

I was told the AXS would have 17 and the AXN would have 19?
This is wonderful!

Here is the picture, maybe I'm missing a bolt? Its dark out. I'm assuming I didn't miss THREE bolts so surely its the AXS then?

http://race3wide.com/pan.png

Actually, oging through my other pictures I think that one end is squared off so the bolt that appears to be in both the far left of the far right photo and far right of the middle photo is NOT a duplicate, so that would make the count 17, and assumingly an AXS. I'm just confused because it says the old name of AXS was AXOD-E and the old name of AXN was AXOD

As for the back center, this is what I see. Do you see the VSS? Is this even the right place to be looking?

http://race3wide.com/back.jpg

As for the A/C, when I turn the A/C on the car begins to sound as if there is a squeky belt and perhaps a slight vibration. I turn the A/C off immediately so I don't experience it for long. It is isolated to the moment I turn the A/C on, and ends the exact second I shut the A/C off. It has never occured at anypoint when the A/C was off, and occurs every single time the A/C is turned on. I did notice this at the start of summer but never happened before this year.

My purpose for asking which engine you have is because I can pull up the electrical wiring diagram for the particular engine, then use the component locator that way. Going the route of the transmission strangely did not list the VSS for me.

I have since found the VSS section based off of transmission since you didn't provide the engine info, but it doesn't show physical location. For the AX4N transmission it says you need to get to it from underneath, after you remove the dual converter y-pipe and VSS shield. There's also 1 retaining bolt that holds the VSS into the transaxle. It appears that if you have the AX4N transaxle, the transmission pan will say AX4N where yours shows AXOD. The AX4N has 19 pan bolts. The long straight end of the pan will have 4 pan bolts.

The AX4S transmission has 17 pan bolts according to the factory service manual. The instructions to remove the VSS from the AX4S are similar to the AX4N, but the VSS appears to mount horizontally with respect to the transaxle housing rather than vertically for the AX4N. It appears to be towards the end of the transaxle housing which would place it near the center of the vehicle. The long straight side of the pan will have 3 bolts.

-Rod

The only thing it says on the engine is '3.0 V6'

I couldn't find anything else bar a sticker on the side that said 'DR', or anything further about the engine. The guy at Autozone also asked me about the engine, but then said it "didn't matter" the only thing it depended on was the transmisison

Just go to your local Ford dealer and give the guy at the parts counter your vin# and ask him for a build sheet.

Just go to your local Ford dealer and give the guy at the parts counter your vin# and ask him for a build sheet.

As (I believe?) I have already said, I already gave the vin# to Ford and the only thing that they were able to tell me was that the transmission was a 4-Speed Transaxle (or something to that effect) nothing more specific about which actual type of transmission it was.

The flat side has 3 bolts and I counted about 16 So I'm fairly sure it has to be the AXS.

Well thats BS! Go to a different dealer then! The vin# provides every detail about your vehicle down to the lug nuts.

So I went to Autozone and he said what I need to know is not necessarily the engine but the transmission type?

He said theres two types for a 1999 Taurus, a "AXN" and "AXS"

So I crawled under the car, and sure enough, the only thing I could find was the letters "AXOD"

I took a bunch of pictures and I'm about to "Count the Bolts" to try to pinpoint which one it is. Incredible that I'm sitting here counting bolts on a photograph because theres no way to figure out which type of transmission I have otherwise. I even pulled up the VIN and the only thing it listed was the generic type not the specific name. Apparently there is a different speed sensor depending on the transmission type.


And when I count the bolts I keep getting "16"

I was told the AXS would have 17 and the AXN would have 19?
This is wonderful!

Here is the picture, maybe I'm missing a bolt? Its dark out. I'm assuming I didn't miss THREE bolts so surely its the AXS then?

http://race3wide.com/pan.png

Actually, oging through my other pictures I think that one end is squared off so the bolt that appears to be in both the far left of the far right photo and far right of the middle photo is NOT a duplicate, so that would make the count 17, and assumingly an AXS. I'm just confused because it says the old name of AXS was AXOD-E and the old name of AXN was AXOD

As for the back center, this is what I see. Do you see the VSS? Is this even the right place to be looking?

http://race3wide.com/back.jpg

As for the A/C, when I turn the A/C on the car begins to sound as if there is a squeky belt and perhaps a slight vibration. I turn the A/C off immediately so I don't experience it for long. It is isolated to the moment I turn the A/C on, and ends the exact second I shut the A/C off. It has never occured at anypoint when the A/C was off, and occurs every single time the A/C is turned on. I did notice this at the start of summer but never happened before this year.
Hello..I am Having the same problem..Axs 99 ford taurus 3.0...17 bolt Part cost 15.95 its located On the Back side of Tranny..Its a Bear to get to But if you can get a person to help guide youto the Bolt It shouldn't be bad..Speed sensor..Anyhow that should Elimate the Speedo and shifting problem.. Hope this Helps Jimmy

Oh Yes AXOD The OD Is Overdrive...fords Gor to love em LOL

1) stand on the drivers side of the car by the fender

2) use a flashlight to look into the engine at an angle. Under cylinder two is the speed senor.

3) reach in and unhook the cable from the sensor

4) use a 10 millimeter ratchet with a short extension to undo the bolt. Be careful not to lose the bolt.

5) pull the sensor out towards you.

After you have the sensor out, you need to remove the rubber thing on the tip (a gear). It has a retainer clip holding it on. Be careful not to lose the retainer clip.

The hardest part is getting the bolt back in after you put in the new sensor.

One thing to note is that both the Haynes manual and the Taurus shop manual tell you to get at t from under the car. I still can't figure out how one would do that.

I would suggest bringing to a transmission shop. My '98 Duratec was doing the exact same thing. They examined for free. It was the VSS, they replaced for $315. The old one came out in pieces as it was rusted so badly. I wouldn't even attempt to mess with this one myself. Know your limits!

I would suggest bringing to a transmission shop. My '98 Duratec was doing the exact same thing. They examined for free. It was the VSS, they replaced for $315. The old one came out in pieces as it was rusted so badly. I wouldn't even attempt to mess with this one myself. Know your limits!
Bollocks.

I fixed it myself and spent $15.99

Its not the easiest part to locate, but here is my advice.

1) Take off the right front tire. You will see a round tube shaped part of the car with a metal clip around it, this is the clip for the heat shield. Just pop off the heat shield, because you won't be able to see the VSS until you do that.

2) Follow the steps above

3) The way I found easiest was putting a piece of cardboard over top of the engine and just lying down over the engine, I brought a mirror with me, located the VSS and that was it. Just get the bolt off, pop it out, swap the end to the new part and screw it in.


The hardest thing was trying to get a clear description of where on the car it was, as everyone seemed to think it was in a different place. Once I located it for myself, it was relatively simple, and I saved $300.

Well thats BS! Go to a different dealer then! The vin# provides every detail about your vehicle down to the lug nuts.

Actually, the VIN does not provide transmission information. The transmission code is located on the label on the drivers door in the block labeled TR, which is item 9 in the picture.

Code T or L is an AX4S and Code X or N is an AX4N.

http://i110.photobucket.com/albums/n113/rdh2/label.gif

Right. The VIN actually provides suprisingly little data as to the options and build data of the car. That's what a "build sheet" is for.

Straight from Ford, their VIN provides the following:
Position 1-3 World Manufacturer Identifier
Position 4 Restraint System Type [Brake Type and GVWR Class (Trucks and Vans Only) ]
Position 5-7 Line, Series, Body Type
Position 8 Engine Type
Position 9 Check Digit
Position 10 Model Year
Position 11 Assembly Plant
Position 12-17 Production Sequence Number

-Rod

I have the same problem with my 99 taurus, but my odometer stops counting when the speedometer drops to zero, and occasionally the tachometer drops to zero also. Would the vehicle speed sensor also cause this problem or would something else possibly be wrong?

Welcome to the forum! The VSS would not cause the tachometer to drop to zero. That would either be an issue in the instrument cluster common to both gauges, or the Camshaft Position (CMP) sensor has an issue. The tach signal is sourced from the CMP sensor.

-Rod

@shorod

You are clearly a pro at this, especially this model. Thank you very much for spending your time here helping us!

I experienced the zero MPH symptom today while driving home, and my car wouldn't shift from 1st. Suddenly the speedometer started working again, and it shifted. I feel my problem is the sensor you mentioned above, and plan to take the steps to replace it.

A side question:
Would a faulty sensor of this type also cause "jerky" behavior while cruising in OD?

Welcome to the forum!

Yeah, a faulty VSS could cause jerky behavior when in OD because the computer is only supposed to let the OD engage at sustained speeds above something like 35 mph. If the VSS drops out momentarily, the PCM will probably try to disable the OD which you may feel as a jerkiness.

-Rod

@shorod

This makes so much sense. Hopefully I will be able to replace this sensor this weekend.

I have been monitoring my gauges knowing what I now know, and have noticed the speedometer slightly jumps or lags very seldom. I would not have noticed it before, but now I know what to look for.

Something new happened. I was driving for over an hour, then went to a store and turned off the car. When I started it again and left the store, it would not shift from 1st gear. Then on the cluster, a green light flashed that reads 'O/D OFF'. I understand this cluster was probably used in several different models, as I don't have the ability to disable O/D. Actually I don't think my car even has O/D.

So my question is does this flashing 'O/D OFF' indicate anything else, or would it still lead to the same sensor?

Thanks again for all you do here!

What year is the Taurus you have, and do you know which transmission it has (see post #19 above)? I would be quite surprised if your car does NOT have OD and if you are not able to turn it off. Do you have an owner's manual for the car?

That being said, the flashing likely indicates that the transmission has identified an issue and set a diagnostic code. Unfortunately since the OD Off light is flashing rather than the Service Engine Soon / Check Engine light, the common consumer-grade scan tools will not be able to retrieve the transmission diagnostic code. That will instead require a professional scan tool. There are far too many possible issues that could cause the car to remain in first (or more likely 2nd) and set the OD Off light to flash to speculate without know what the code is. If that happens again (or is still happening) you might try manually shifting between the low gears to see if the gear select lever will allow you to access different gears.

-Rod

Determining what engine is in a Taurus is not rocket science. It is important to know when working on one.

One quick note in replacing vss 1998 Ford Taurus 3.0 DOHC AX4N 19 bolt. I was able to get it from under the passenger side with car jacked up you can get one hand on the bolt and with the other reach up through the a-arm and reach around the alternator, use a small ratchet with a deep socket and 1 small extension. Worked for me, good luck!