Depending on what shaft speeds the unit is looking for, you may able to use the crankshaft sensor for input speed and a tailstock sensor for output shaft speed if there is one available on the transmission. The problem is that they will not sync up with the microcontroller tables and will probably set codes. Just a guess but the logic won' t be the same. As I said before, may be easier to adjust the ECM than try to fool it. Find a good programmer who can hack it and rewrite the software. Not the first time it has been done and a lot easier on the mind and the pocketbook.

 

Depending on what shaft speeds the unit is looking for, you may able to use the crankshaft sensor for input speed and a tailstock sensor for output shaft speed if there is one available on the transmission. The problem is that they will not sync up with the microcontroller tables and will probably set codes. Just a guess but the logic won' t be the same. As I said before, may be easier to adjust the ECM than try to fool it. Find a good programmer who can hack it and rewrite the software. Not the first time it has been done and a lot easier on the mind and the pocketbook.

So I liked what you were saying earlier about sniffing the CAN BUS network to see the park and neutral signals sent. I think that would also be useful in seeing the signals between the shifter and TCM. There is no output speed sensor on the transmission, so that isn't a worry. Throttle position and MAF sensor dictate fueling for the engine so the car driving in neutral should be fine. I see you can use an Arduino and some simple programs to read CAN BUS traffic, but could such a system interpret analog signals and turn them into CAN signals to send into the network? I've not messed with Arduino at all. It would be nice to use such an Arduino to act as a go between with the gear position switches, for instance pressing neutral on the dash would tell the Arduino to send the "neutral" CAN signal into the car's network.

 

You could try something like this:
https://gridconnect.com/usb-can-interface.html
That way you don't need to build anything and easy to work with.

 

I'd look at getting a new ECM that was used for a manual tranny and that engine. Automatics aren't as popular in Europe so they should be able to be bought from there through Mercedes. What are you going to do for all of the other stuff involved, flywheel, clutch pedals and linkage etc?

Have you checked with any of the engine swap places? There are some companies making stand alone modules for stuff like this. Painless is one of them, or maybe Jaguars that Run.

If you want punishment , climb mount Everest or take up whitewater rafting , don't put yourself through this it will never work satisfactorily. TCM connects to the Engine ECU via CAN , there is also ABS/ESP to think of. The transmission shift lever on this car is also a computer and will need to be retained if you insist in keeping the TCM. If so how do you expect to control the manual shift gearbox?
ECU fuelling is very dependent on correct information from the transmission & TCM and while it may work in some form it will have poor driveability, terrible emissions and lousy MPG. Fit the equivalent manual transmission engine ECU (as previously advised) and your only issues will be sorting out the immobiliser , stability control and the differences in the wiring. My advice is try and do a deal for the lot with some breakers yard for all the stuff from the same car - it will be many many times cheaper than what you propose and the car will have some value when you are finished. Doing what you propose would render the car worthless even if you did somehow manage to get it to drive.

 

If you want punishment , climb mount Everest or take up whitewater rafting , don't put yourself through this it will never work satisfactorily. TCM connects to the Engine ECU via CAN , there is also ABS/ESP to think of. The transmission shift lever on this car is also a computer and will need to be retained if you insist in keeping the TCM. If so how do you expect to control the manual shift gearbox?
ECU fuelling is very dependent on correct information from the transmission & TCM and while it may work in some form it will have poor driveability, terrible emissions and lousy MPG. Fit the equivalent manual transmission engine ECU (as previously advised) and your only issues will be sorting out the immobiliser , stability control and the differences in the wiring. My advice is try and do a deal for the lot with some breakers yard for all the stuff from the same car - it will be many many times cheaper than what you propose and the car will have some value when you are finished. Doing what you propose would render the car worthless even if you did somehow manage to get it to drive.

Huh? I'm not the one doing this. What you said is pretty much what I was talking about. Some of us do things like this to improve/hot rod cars, we don't care all that much about resale value. But there are people that will pay a lot of money for a car changed away from stock, that run faster and better in performance.