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Discussion Starter · #1 ·
I think I messed up good on this one. Trying to diag an inop coolant gauge in my instrument cluster, I swapped with another used instrument cluster, which also didnt work. So I reinstalled the original cluster and now I get the odometer error message on the display. The only scan tool I have available that reads the becm is EAS unlock tool by RSW solutions. There is no function listed to sync mileage between becm and instrument cluster, but there is one that shows mileage in becm. This now reads 197k, while the vehicle only has 133k! Guessing this would be an error of the becm. whats the best way of repairing this before I mess things up even more?
 

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Unfortunately, the mileage is stored in both BECM and IPC. if you replace either unit, the higher mileage of the two will be accepted and agreed upon by both modules as well as the odometer error light.

the only recourse I know of would be a brand new BECM and IPC, or to dump the firmware of the BECM, modify it to the correct value and reflash, and remove and reflash the increment chip on the IPC. Option A would be incredibly expensive and option B would require specialized equipment and skills
 

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Discussion Starter · #3 ·
damn. thats a terrible design on land rover. why would it just take random info off another instrument cluster? as for option b, who would be the person to talk to with the specialized equipment and skills?
 

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I would imagine the system is in place to prevent somebody from slapping a 50k cluster into a 200k truck and selling it as a 50k truck.

I haven't fully investigated the relationship between the two computers, but I doubt it's as simple as changing the mileage value. there's likely a checksum shared between the two computers, and you would have to calculate a new checksum and upload it to both computers so that they had consistent mileage and checksums, otherwise red error light.

I sincerely doubt you'll find a shop to do the work, as it's potentially felony fraud tampering with that equipment if they can't verify the actual mileage:

"Altering the mileage reading on a motor vehicle is a felony. Effective July 5, 1994, the odometer tampering statutes were recodified from Title 15, U.S.C., to Title 49."

Yes, you'd be "correcting" the mileage, but that's a tough sell.

a nanocom or GAP tool should be able to dump the BECM into a binary file. I wouldn't expect the information to be obfuscated, and could possibly be edited with a simple hex editor before rewriting. my understanding of the gauge cluster though, is that the actual clock chip will need to be removed from the board and reprogrammed. The chip likely has write-protect to keep it from being flashed in-situ. Again, it may very well be more complicated than that, as the IPC may cache the mileage somewhere else and balk at a reset mileage chip. if it's a standard IC, you could probably remove with a soldering iron. if it's a BGA, you'd need a hot air station, solder paste, a BGA template... and more skills than even I have in that capacity!
 

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Been here with mine. There is not a solution. The P38 shares the same electronics & HVAC as the E38 BMW. I own one of these too. It is a problem with both cars. Neither BMW or Rangie sites have found a solution that is economical. I just put up with it. It only affects resale value & I dont sell cars. "Collect, Improve, Leave for the kids" lol.
 
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