My speedo has stopped working

[GlynRS2]

Driving along this afternoon & my speedo just stopped working:mad:
Bit difficult to judge your speed without it, so just moving cautiously along with the flow of traffic & praying to avoid any hidden cameras.
I guess the most likely thing is the gearbox speed/distance sensor which is reasonably inexpensive.
Odd thing is though that the computer is still happy to give me mpg & range readouts , but I thought that took its info from the same speed/distance sensor?
All other dash instruments/electrics appear to be working fine.
Is there anything else I should check first?

I am not too bothered as I have a cover everything warranty, but it would be good to get the speedo back asap, while I still have a licence!

[SteveH]

You may find it will come back on it's own. Mine stopped in the middle of a long journey. Next worning I started the car and it was fine, it has never happened again. It could just be a loose connection, or as you say, the gearbox speed sensor. Good luck fixing it

[GlynRS2]

Interesting thing I noticed on the way home tonight - the mpg readout is now stuck at what must be a default value of 15.4mpg - and I was driving carefully to watch my speed, honest.
So I guess it must be the speed/distance sensor, but I will check that it isn't just a loose connector first.

[marty]

mines gone intermitant but I think its somthing to do with me pressure washing the engine when i changed the radiator. havent had time to check it out yet works first of then after about 5 miles starts playing up like a loose conection when it doesent work trip fuel distence etc dosent work either

[Lee]

Check sensors and wiring first. If it is the speedo head in the instrument binnacle then I have one available if needed. It's from the 170mph speedo but imagine it is the same stepper motor used in both S2 and RS2 with recalibration done on the binnacle PCB.

[porkkis]

It's one signal from the sender unit that is used at speedo, odo, aircon, cruise, radio (if original), read diff control unit so one ground shortage somewhere stops all related functionality.
Of course the MPG reading is also showing the default when no speed signal is present. Impossible to calculate those things without it.

You can check if it's a instrument cluster problem by trying the rear diff. If it doesn't disengage automatically the problem is more general. Possibly the sender at gearbox or shortage.

There should be some connecting point where all the white/blue wires spread all over the car from. Dunno where it is.

My signal is also lost sometimes. Really hard to hunt the fault when the problem doesn't stay.

[GlynRS2]

Thanks for all the replies.
I'll take a good look at it later.

Cheers

[Stick Insect]

I had problems with my speedo then it seemed to work ok. My speedo works nearly all of the time but the MPG display works only very occasionally. it shows 5.4MPG all the time apart from when i back off the throttle and it then goes to 99.9MPG I wish!!

I have tried a spare instrument panel ( without computer) and the speedo works on both or neither.

Please see my thread:

http://www.s2forum.com/forum/showthr...&threadid=1589

a few reads but no replies

I was told the ABS sensors had some 'input', this was told to me by a very good motor engineer, however I think Porkkis is right. I will check my earths......

It would be nice if it worked tho'.

David

[Ski]

speedo's who needs em? they lie anyways..

untill u fix ur speedo, and u wanna make sure your not driving over the limit, just turn ur computer to average miler per hour and reset it while at stable speed. This will give u a true representation of ur speed.. unlike the speedo does

[GlynRS2]

Update on my speedo - car has been at Audi Crawley for past 2 days - luckily under warranty.
They have changed the gearbox distance sensor (not sure why as this had been done already & didn't work), not surprisingly it didn't work the second time either.
So they changed the speedo (not cheap, so thanks for the warranty) but still doesn't work. Hopefully they will refit old speedo so I keep the correct mileage reading.
So now they are checking the loom between the two.
I will let you know what transpires, as it may be the same as some of you other guys are getting intermittantly. It is probably going to be something simple, but I dread to think what the labour charge is going to be:eek2:
The only good thing to come out of it so far is that they changed the outside temperature guage for good measure as the back light bulb had gone.

[porkkis]

This is what you could do by yourself: Take a DMM and measure that the white/blue cable isn't connected to ground somewhere. Wire failure anywhere the system stops all functioning. Easiest place to find a white/blue wire could be the rear diff control unit. Dunno where it is in avants but in coupe it's under the rear seat.

[*ZenithalRavage*]

Hey my mileage counter is starting to die. Every now and then the counter doesn't move, I don't like this, I want a real milieage if you know what I mean, could this have to do with the same sort of problem? Is is a different sensor?

[Michel]

Isn't the mileage counter a mechanical link to the speedo unit?

I have had trouble with this wearing on other cars and being affected by high and low temps as expansion and contraction of worn gears etc made it all hit and miss.

Can the speedo itself be taken apart and refurbished?

Certainly for older cars this is an issue and there are people who can do this, but have not heard of it for moderns....

[Sidspud]

The mileage counter and trip counter are both mechanical. It is possible to disassemble the speedo, but its very fiddly and you'd probably end up with the numbers out of alignment. You don't want this because it will look as though the car has been clocked.
When my speedo died, I replaced it with a new one showing 1 mile! I've kept the original one, so that if I ever sell the car I can show the true mileage to the prospective buyer.

[*ZenithalRavage*]

Originally posted by sidspud
The mileage counter and trip counter are both mechanical. It is possible to disassemble the speedo, but its very fiddly and you'd probably end up with the numbers out of alignment. You don't want this because it will look as though the car has been clocked.
When my speedo died, I replaced it with a new one showing 1 mile! I've kept the original one, so that if I ever sell the car I can show the true mileage to the prospective buyer.

hmm.. interesting stuff, didn't it feel weird to have a counter showing 1 mile? Did it make u thrash ur car a bit harder hehe
Anyway, I would prefer having this counter continue, do you think it would be just as much work to repair it as to replace it with a new one?