Speedo Droping To Zero

[nigel129]

Hi all, looking for some clearer carification on a Speedo problem i think ive dianoised myself.

As the topic suggests my speedo drops intermitantly to zero, Ha i thought, the "VSS" on the gearbox. Has a MOT chap take a quick look at that and he said, visualy it looked fine, wel not loose at any rate.

However, reasearching the prob further, ive come across some things id like to clarify.

My Mk 6 1.3 does not have ABS so how does this affect diagnoisis ?

As well as speedo drop off, the odometer also stops. I think ive read that this may not mean its the VSS. (kepps the mieage down though LOL) Is the a wheel sensor on a non ABS ?? Or could it just have electronically failed.(vss i mean)

How do i carry out this test (thanks to digidan) http://www.fordowner...or/#entry127799

While this is stil at fault, ive read it can slightly affect fuel consumption as it appears that the rev counter rises, not really an issue but over an extended period could add up running costs.

Sorry to start a new thread but dont want to hijack somones eleses headaches.

Thanks

nigel

[Stoney871]

Definitely the speed sensor, it may look ok but it's the internals that usually pack up.

I'd start by checking the wire from it for damage and that the plug is secure.

The Speedo and odometer dropping together is a clear symptom of failure.

The only way to really diagnose the sensor is to replace it, you may get fault codes but not guaranteed.

Do you also find that the engine power drops too?

On a focus it does but interested to know if it does the same on a fiesta.

[gforce]

I'd agree with the above. It happened on my Focus where I'd no speedo and the mileage didn't go up. I won a sensor for 99p on eBay and swapped this out myself, but it didn't fix it. Car was goin into the garage the following week anyway so I left it to them and there was a loose wire somewhere. They fixed it and no issues since.

I'd check the wiring first as you may not need a sensor, I just got lucky getting one on auction which is why I did this first.

[nigel129]

Thanks lads, So it ooks like a new VSS, £22.ish off eBay as theres not one on auction at the mo (just my luck). Didnt want to splash out on one only to find out it may have been somthing else, but your experience and advice has been a great help. Will post again when job done.

Thanks again.

Nigel

[gforce]

Sorry mate, just to clarify...on my 55 plate Focus it was simply a loose or broken wire somewhere that my mechanic ended up sorting for me, not the sensor itself. I put a new sensor in (cos it was an easy job and I got it cheap) but this didn't fix it until he looked at the wiring. On mine though, it was the ABS sensor which provides the speed sensor info as well, so maybe it's a bit different on your Fiesta.

But I'd maybe check the wiring first as it may not be the sensor itself. Keep us posted anyway on your progress, sorry I can't be of more help!

[nigel129]

Hi Guys, yup its been a while but ive been off my feet for some time. Ive been waiting for a mate to fit the new VSS but hes busy as hell so i thought id ask if its somthing i can have a go at my self.

Ive read it can be accessed under the battery tray BUT can it be replaced this way or just seen.

If so, how difficult is it to remove the tray/box, tried looking it up and drew a blank.

OR should i wait till mate can get car on a lift.

Ive also got a new pin ready just in case, local dealer actually cheaper than eBay for the pin, by a whole 2 pence LOL

thanks

nigel

[nigel129]

Bump

[Stoney871]

You should be able to access it from the top but may find it easier to get to from undernearh.

[nigel129]

You should be able to access it from the top but may find it easier to get to from undernearh.

Thanks, looks like a ramp or lift job then. Cant say i was fussed on trying to get the battery box out only to find half a dozen other things in the way.

nigel

[nigel129]

Arrrrrgh.... Ok, My mate got it up on the lift, havin had a look past the battery first and deciding puttin it on the lift was easier... BUT he noted that there was part of the exhast in the way, the maff sensor and a strut of some kind. (soz reapeating this from memory. Any way, he started to pull at the pin with a right angle end pliers on after a few mommnets ONE end of the pin AND NO PIN.

Basically whats left is the center of the fixing of the bit that looks like the end on a pen clip.

Does anyone have any idea what to do now, drilling it out doesnt seem an option even if it was more accesible.

Heeeeelp !

nigel

(basically the job stumped for the sake of a 1.50 pin, so much for having a new one ready !

[nigel129]

BUMP

[Stoney871]

I have seen the pin snapping off before, it takes a bit of fiddling and some force to remove it but it will come out in the end.

A friend of mine (an ex army mechanic) got a snapped one out and repaired any damage to the pin hole with metal putty

[nigel129]

I have seen the pin snapping off before, it takes a bit of fiddling and some force to remove it but it will come out in the end.

A friend of mine (an ex army mechanic) got a snapped one out and repaired any damage to the pin hole with metal putty

Thanks for the info though its not the pin itself thats snapped but the clip. As it looks, theres nothing left now to grab hold of to remove the pin. With the best will in the world, my mate cant tie up his ramp just for me to figure out a way let alone the time it would take to actually get it out,

Thats why i was hoping someone on the forum has successfully removed the pin and explain in detail how they did it (without dropping the gearbox and drilling out).

i live in hope as its running like a pig somtimes, and im dam sure my fuels gone up by £10 a week just on the school run.

nigel

[Stoney871]

Taken fron a Honest John Post, hopefully makes things clearer/easier.

Vehicle Speed Sensor - removal and refitting

1. Access to the speed sensor is easiest from below. Apply the handbrake, then loosen the left hand (passenger side) front wheel nuts. Jack up the front of the car and support it on axle stands.

2. Remove the left-hand front wheel and the wheelarch liner - the sensor is located next to the right-hand driveshaft, at the rear of the transmission.

3. Disconnect the wiring plug from the top of the sensor.

4. Using thin-nosed pliers, pull out the retaining pin at the base of the sensor, noting how it is fitted.

5. Pull out the sensor and be prepared for a bit of oil spillage.

6. To fit the new sensor, just reverse the procedure - lightly oil the rubber o-ring on the new sensor first.

Here are some helpful tips for the above points :

2. I think I could have possibly done this job without removing the wheel or the liner. Removing them did, however, help us with removing the retaining pin which was stuck - see tip 4. To remove the wheelarch liner, there are a total of 6 screws to remove - 2 each side of the suspension, one connecting the liner to the front bumper at the bottom and one bolt securing the bottom rear of the liner to the sill.

3. It'll take you a while to find it, as it's not immediately obvious. The Haynes manual does have a few pictures, but it took me a while to find it even with the pictures ! Have a look at your new sensor - the arm with the hole that protrudes from it makes it easy to distinguish it from the other sensors that you'll be able to see under there. I would actually describe it as being on top of the transmission so you'll need to reach around to be able to grab it. I found a torch was essential.

4. This was the bit that I struggled with. The steel retaining pin has a clip attached to it and tugging on this just caused the clip to break off. It soon became apparent that the pin was well and truely stuck fast. To remove it, I had to break off the plastic arm from the sensor to enable me to be able to grip the end of the pin tightly with mole grips. A friend with a long chisel and hammer was then able to tap away at the mole grips with me tugging with each hit, until the pin came out. He was able to position the chisel through a gap where the wheelarch liner would have been and hammer away from there.

6. Putting the new sensor in was fairly easy - it just needed tapping gently down with a hammer. Despite breaking the clip off the steel retaining pin, I decided to reuse it as it goes back in so tightly that I don't really think that the clip was doing anything anyway. (If you're not sure, then get a new retaining pin before you start the job !) NB. Make sure you leave enough of the pin sticking out to be able to remove it in future !

I've done a few jobs on cars before and didn't find this one too hard - the manual desribes it as 'fairly difficult - suitable for the competent DIY mechanic'

Removing the pin was the hardest part. My Focus is just over 5 years old so you may find the pin easier to remove if yours is newer.

If the dealer price of £100+ for that job is correct, then I guess I saved around £80 by having a go.

Hope this is helpful.

One last thing - even with the plastic arm broken off your old sensor, you still won't be able to remove the sensor until you've removed the retaining pin as it is held in place inside the cavity by the pin too. Trust me - the job would have taken about 20 minutes less if I'd have realised this sooner....

[nigel129]

WOW just the god dam ticket, better than id hoped for, i can print this off now, leave my friend digest it for a day or two (while soaking the area in WD40 as well) and see if we can have another go at it, Brilliant, cant thank you enough, as does my wallet. Will keep you updated.

thanks again,

nigel

[Stoney871]

You're welcome any time Nigel.

I know that the VSS is a royal pain to sort out, so anything i can do to assist is my pleasure.

Put it this way, if you go to a Dealer they will insist that you need a diagnostic (at least £75) just to tell you what you already know, charge you probably 2 hours labour, their price for the part (which always seems higher than you can get it yourself, but god forbid you ask them to fit a self sourced part) and then tell you some codswallop about this part or that part also needs doing.

For £20-£25 and a few knuckle scuffs and copious swearing i know which i'd rather do.

Final pointer though, do not for the love of all things holy snap the sensor off when removing it, that is a whole other level of hell.

As you said, copious amounts of penetrating fluid, and a firm but steady hand will see the job through to completion.

[nigel129]

Hmmmm not as easy to WD40 as i thought it might be, seems to be some sort of silver tape 2 inches above the top of the sensor, can a remove this tape ??

nigel

[Navarro93]

yes, you can. the silver tape is just head shield tape. On another note, I've managed to get my pin out (after snapping the clip off lol) and even with the pin right out I still can't get the bl00dy sensor out. I've tried wiggling, twisting, levering and tapping, but it just won't bl00dy budge.

any hints or tips from experts?

[james1000000]

so basically this vvs is located ontopofthe gearbox,,,,,under the battery tray