MFA Display MPG Part Not Functioning

Hi All,

My MFA has stopped displaying MPG figures and the other fuel related info.

The oil temperature, Time and trip time still function.

Has anyone ever encountered this and if so how is it fixed please?  Is it something to do with the vacuum pipe or is it the pickup on the back of the speedo? 

Id try taking the battery lead off first or pulling the fuse, leave for a few seconds and replace. See if that helps. 
If not the vacuum pipe as you say would be my next call. 

Dano said

Id try taking the battery lead off first or pulling the fuse, leave for a few seconds and replace. See if that helps. 
If not the vacuum pipe as you say would be my next call. 

Thanks Dano,

I've tried the battery trick, and also the fuse seperately.  What inputs or sensors actually contribute to that part of the display please?

I don't know specifically. It's all on the printed circuit in the rear and they have a tendency to fail due to breaks in the circuits. 

Why did it stop working in the first place? Had you been working in any specific areas??? 

Dano,

Nope.  I've had issues with the rev counter before and that was a brittle CB.  Perhaps I'll do a trace on all lines on there.

Thank you.

Doesn't it get its feed from the square type reverse light switch on the gearbox? There are 4 wires going into it, 2 for the reverse light and 2 for the MPG figures.

The mpg relies on the vacuum line and a small sensor on the back of the speedo. The little vacuum unit can fail and it is possible to replace it.

do the avg. speed and distance settings work?