Speedo Drops To Zero

[UncleFesta]

Hi Folks

I have a Mk6? I think Fiesta 1.4TDCi on a 52 plate and it's developed an annoying habit over the past few months. The speedo drops to zero randomly. Sometimes it will pick up again after a few minutes other times it will stay at zero for ages. This means I'm not registering mileage either. Can someone tell me where the speedo is picked up from. I've looked in the Haynes book of lies and general untruths but it only shows the ubiquitous chip on the instrument cluster with no clues as to where the speedo feed comes in. I presume it comes off the gearbox somewhere and I'm guessing it's a bad connection that makes and breaks. Any good steers as to where to look would be useful. Thanks

Dave

[mintalkin]

your vss (vechial speed sensor) should be at the back/top of the gearbox

[UncleFesta]

your vss (vechial speed sensor) should be at the back/top of the gearbox

Thanks

I'll have a look there

[UncleFesta]

Thanks

I'll have a look there

Found the vss..... that's not designed to come out with the engine in situ is it.....

Access from above is limited by the stupid routing of brake pipes that suddenly jut out into the only gap in the engine bay on that side and access from underneath is pretty restrictive too. Guess I'll be living with the speedo dropping off for a while then. Interestingly a side effect of the speedo not working is that the revs rise slightly during gearchanges.....

What causes that then?

[mintalkin]

the vss sends signels to the ecu so it can effect the running of the car.