Hi guys, i've got a problem with my SL500 r230 2006. The car is not cranking at all, the key is stuck in the ignition switch and transmission is locked in P. Both batteries are good, all the fuses were checked and found only one broken 20A in the back of the passengers seat, replaced and still nothing. Also i've got a S letter on the right side of the screen. Does anyone have an idea what this could be?

S means sport mode,

Did you check the 7.5A fuse just in front of the rear battery? This fuse powers the ignition/key lock.

You can only get the key out when the shifter thinks or knows it's in P.
That is a mechanical link only, via a cable from the shifter to the ignition barrel which locks the key via the two prongs on the key.
With shifter in neutral and battery disconnected, when you put the shifter back to P the prongs on the cable unlock the key and you can take it out. So deal with that first, remove the console and trim and find out where the mechanical link is broken.

This will shed some light on the no start issue - you won't get drive authorisation until the shifter/EIS/ECU handshake is made.

You have an issue in the shifter I think.

Are you getting the ignition lights? If so then you have power to the EIS.

Yes, the ignition lights are comming up

After disconnecting and connecting battery I don’t have ignition, the car is not locking and unlocking and windows are not working

Please give us a more detailed update as I keep thinking about what your problem is.
Is the key still stuck in the ignition? Presumably in the position between ignition on and removal?

And now you say you disconnect battery (rear one?) and now the stuck key does not turn to the ignition position? Or it does and nothing turns on?
Your Red battery light indicates there is a battery problem. Confirm that when connected, both read at least 12 Volts.

Besides the fuses in the fuse boxes, there are large "pre-fuses", two in the box just in front of the rear battery and six in a very-difficult-to-access box in the passenger footwell.

If the car now seems completely (or almost) dead, perhaps this recent thread would help you understand the pre-fuses and such:
https://mbworld.org/forums/sl-class-...tely-dead.html

In that thread, the OP found a bad pre-fuse in the back.

BTW - if you start disconnecting and re-connecting batteries, be sure to disconnect the rear one first, and when re-connecting, reconnect the front one first. Otherwise you will get the Red battery light. (I just did this morning because I forgot the front battery was disconnected.)

Break the problem down and don't assume the issues are related.
Red battery light is nothing to worry about for the moment, that can be dealt with later. The car will run with that message.
If you just dis/connected the batteries in the wrong order then the code will clear on the next start/stop cycle.

First check the 7.5A in F33 and if that's good start looking at the EIS module. Make sure it's getting power. If fuse is OK it is likely that it's gone bad but may be fixed by removing it and checking all the connections, or giving it a rock and a thump. Worth a try.

But start with the key issue - you'll have to remove the wood console trim to see what's going on in the shifter. If the shifter thinks it's not in P then it will never run.

What a nightmare! Hope you get it figured out quickly. I sure would like to hear how you ultimately resolve this.

Thank you guys, I managed to disassemble the front trim and saw the link was not in place and 2 connectors were disconnected. After plugging in everything is working perfectly apart from the red battery light on the dash

Well, that is good news indeed!
Curious, when you say "link was not in place", was it at the shifter or at the EIS? At the shifter, it is first inserted and then turned 90 degrees.

Use a scan tool to clear any battery codes and see if that clears the Red battery light.

At the shifter, do you know any good scan application for iOS? I used a car scanner, but it doesn’t work or maybe vgate icar pro is a bad scanning interface?

By front trim are you referring to the gear selector area? Is that where the problem was?

Thanks for the update OP, glad you figured it out.

exactly

Foxwell or Launch Creader for MB to clear the code.