1999 Z3 where is the mileage stored

[Digger908]

I replaced the code chip in the cluster with a new one and now it reads 25000 miles higher
I've had it to the dealer and they said they can't fix it. I'm wondering if it was rolled back so to speak?

[328 Power 04]

Only stored in the cluster.
What did you replace exactly, and why?

[Digger908]

It's a long story. Before I bought the car the usual problem with the cluster ( no fuel, temp gauges and tach) I picked up the car from the dealer where they fixed it. The guy I bought it from said they put a new cluster in but all the dealer showed was a reprogram. I called because it happened again ERROR 01 I installed a new code plug and did the copy thing because the tamper light was on.
I'm guessing a used cluster and in that case my original mileage may be gone forever.
I do still have the old code plug?

[328 Power 04]

Sorry, cluster and coding plug* hold mileage. To me they're both part of cluster.

When you do the test sync function (to remove tamper dot), the coding plug or cluster will take the higher mileage of the two.

If you still have old coding plug, you can only transfer its mileage to a cluster with lower miles.

There are tools that can edit cluster mileage, but it gets complicated.

[Digger908]

Well I guess it must have been a used one. Being that the old plug is corrupt I can't do the sync function. Also I don't have the original cluster. I'm stuck with 25000 more miles.
Thanks for the info

[328 Power 04]

If you have someone around you with a PASoft 1.36 (or maybe even PASoft 1.4 may work), you can roll back the cluster mileage through diagnostics port.. but the coding plug has to be rewritten at the chip level with eeprom programmer tools. The dealer will not be able to do any of that.

[gc325is]

I see you found it

take a look at ...

https://www.bimmerforums.com/forum/s...p-thread/page9

[328 Power 04]

I think it's similar, yes.
The 99 Z3 non M has a ".C02" cluster (software data version), which is much more like E46 clusters rather than E36 clusters.


But the dealer telling you that the ECU/ECM (MS42 in your car) holding the mileage, that's just wrong. The dealer used ISTA-D, which interrogates the cluster for mileage.