A8L_New_England

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Does the code reader indicate the correct mileage?
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Beach55

i went into a few modules to see what i could find,didn't find anything. i contacted a cluster repair place and there reply is as follows:

Have you had the speed sender checked on the vehicle? if the mileage isn't clocking up this is unlikely to be the cluster.

where is the speed sensor located? if it was faulty would the speedo still work because it does.

JohnnyJ

This is complicated. As the speedo works it has to get input from a working sensor somewhere. Maybe Audi had decided to make things difficult by taking the input to the mileage counter from another sensor.
Each wheel has its own sensor to count revolutions and from that compute possible difference in wheel pressure. It is totally feasible that the mileage counter get input from those sensors.

If you're willing to go down an unusual route to troubleshoot, you can try this:
Fill the tyres to recommended pressure. Reset tyre pressure in car computer as usual. Drive for a couple of kilometers and drive in to a gas station where you can fill (or empty) the tyres. Let out air of one wheel so it is like 10% below recent value. Do not reset the computer set pressure.
Drive for a couple of kilometers. You should get a warning that one of the tyres has too low pressure. Ideally you should now repeat this for the remaining tyres and always get a warning.
When completed you know that each wheel sensor is working ok and do not need to be replaced.
During this process, has the mileage counter changed? If it has, that's a clue to further troubleshooting.

MP4.2+6.0

What is history of car? Did you just buy it? Did you see it working previously?

There unfortunately are now devices that can be used to stop an odometer. Thoroughly illegal, but known to exist. If you just got car, possible though dumb by seller to leave it set as such. If you saw it working in past, then ignore this thought.