Robert 100E

Sometimes the speedo stays at zero - go a long drive and it wakes up, eratic at first then after about 30 miles shows the speed accurately.
The milometer often stops too as does the odometer (trip meter). In wet cold weather, the speedo needle may never move, but in the summer it can be better. 80 mile journey, 30 miles on the clock...
I have read of a dry solder somewhere on this forum before, but can't find it now... is this relevant... someone said instrument cluster may need replacing.
A mechanic said the speedo controls were in two parts, part in the transmission (gear box) and the other behind the dash and said special equipment was needed to diagnose whether I needed a top unit or a bottom unit - claims sender cable is OK... but then someone else said the two parts communicate by "radio waves" or similar!

Model is 1989 - UK - Audi 100E 2.2litre

Does anyone know exactly what the problem is - judging speed by the Rev counter ain't easy.

Najarian

Try this link (if you haven't already). This guy helped me fix my ABS system. Hope it helps

http://members.aol.com/c1j1miller/body.html#Fixing%20the%20electronic%20spedometer

ARK

the instrument cluster PC board (common problem, easy fix), or the vehicle speed sensor, or the interconnecting wires. Most likely the solder joint.

Robert 100E

While the speedo needle doesn't move or jumps around wildly, the Rev Counter is steady (I use it to judge the speed)- does it not get it's data through the same cable (I have no idea ! ) ?

ARK

the speedo. The connection to the speedo can fail independant of the odo.

Robert 100E

In fact the milometer and odometer can restart when the speedo needle starts bouncing around - but it does affect all 3 of them.... even wondered if pressing the odometer reset switch, sometimes stopped the odometer and subsequently stopped or disrupted everything else?

It works better in the summer weather, but in the wet cold winter only moves on long journeys..., especially when the heater has warmed up the car.

RTDog

I'm having a very similar problem with my 94 100. The speedo works ok in warm weather, but in the cold it takes a while to start registering a good speed. The odo works fine all of the time.