RDL0100

At the risk of getting hooted off the board (hooted, not booted), I have what may be an embarrassing question. I have a 2005 SL600. While I have never paid any attention to it, when perusing this board today and after checking the owner's manual, it seems that the SL600 should only have the "C" and "S" transmission modes. However, when the "C/S" button is pushed in my car, I get the "C", the "S", and I get an "M," which the owner's manual suggests is only found on the SL55 and 65. Does that mean that at some point (I purchased the car used) the car was given a ECU and TCU upgrade? There were no badges or paperwork that would suggest that happened and I would have no idea how to figure it out. No dealer has every suggested that was done.

What do you think?

F1BHP

Yes someone had done a ECU/TCU upgrade, it will give you the manual mode.

Dostovel

I have a 2008 SL600 and Eurocharged did my ECU/TCU tune and I didn't get a M mode =(

F1BHP

Where did you get the TCU done, you should have the M mode

squid23

I would really like to know more about this. The lack of the M mode is excluding a lot of attractive cars (e.g. SL500 and CLK500) from my next selection so far.

How predictably can you add the M mode?

Can you get in and out of M while the car is moving?

RDL0100

Here is what I can tell you. My 2005 SL600 has the normal "C/S" button on the console. When I push it, I get the C and the S and then I get an M and when the car is in drive, I get a "1". It will not shift out of "1" while sitting still, but as you drive it, you can use the paddles, or the shifter, to move up and down through the gears.

Here's the point. In C or S when you use the shifter to try to manually drive the car, the rev limiter kicks in about 5500 rpm. When you use the "M" mode, the car quits pulling about 6000 rpm, but there is no limiter. As the car was like that when I bought it, I don't know how it was accomplished, but it was chipped, I believe.

BTW, I put it on a dyno yesterday, and two pulls gave me 458.1 and 459 at the rear wheels. I don't know jack about chipping, but I think that translates into about 545 hp at the crank, which also indicates that it has been chipped at some point.

F1BHP

You are still hitting the rev limiter, it is just raised to 6,000 and does not shift automatically it will just hold it at the limiter.

I think almost all the 5 speed models TCU can be tuned for this except the first couple of years 2003/2004. Just going from memory so can't guarantee it. My facelift SL came with the M button however i still had to tune the TCU to get faster shifts and a raised red line.

Dostovel

Eurocharged did my ECU and TCU tune.

And I should probably contact them because when I accelerate from a stop or coming around a right hand turn and the car is in "C" mode, if I put the pedal all the way down, it is a very rough shift into the next gear once it shifts. That can't be good. Doesn't do it when it's in "S" mode though.

F1BHP

I have heard that before 1st to 2nd gear is not very smooth. You do have the same gearbox as the sl65 though as is was upgraded in 2007. You may be able to get your ECU tune adapted a little to smooth the gear shift.

You might want to look at getting the tune done again anyway as the new Eurocharged tune gets around 610BHP.

Dostovel

Yeah I had just gotten the ECU/TCU combo done last August so it's only been 6 months....

F1BHP

Sorry, I got confused with your post and the BHP numbers posted by RDL