[x-tian-230k]

Cory You have a PM.

Originally Posted by CoryU

Actually, MB is currently using 3 different versions of the "new" software in USA cars. Two of them are being used in most E, SL, CL, and S55's. The other is being used exclusively in the G55. There seems to be no indication or reason for using these three "different" versions, and I've not seen any pattern regarding which cars get which software, with the exception of the G.

It is very possible to load the original software the car was built with, but not by an MB dealer, simply because they don't read and save the OE software before doing the re-flash. They simply write over the OE software.

So, why are they reflashing? The air pump in these cars stays on for 120 seconds after a cold start to help light-off the primary catalysts. These air pumps are notorious for going bad after 3-4 years (some fail far earlier than that), and MB is tired of replacing them under warranty. The "main" purpose of this reflash is an attempt to get the air pump to last longer. They are also replacing the relay with one that triggers at a higher voltage as well. As for the decrease in performance most are experiencing, that secret lies with MB.

As for the SCN coding- that has nothing to do with this. The SCN code is what marries a specific ECU to a specific car, and tells it what equipment the car is built with, emissions equipment, engine, etc. Only when a NEW ECU is installed must it be SCN coded. The SCN code is specific to VIN number, not EPROM files. Furthermore, it is not possible to install a used ECU from one car into another for permanant use.