gilly well as far as you question goes what happened I only can speculate.the interior was disassembled and partially missing,and the ignition taken out now with your i'm kind of trying to find missing link.you mentioned das circuit what is that and what components are involved/main components, or which ones would be the culprit enablying key to turn....no need to look up srs component if you don't think there is some kind of cut off for main power/key turning......mb_buddy

Buddy: das (or DAS) is driver authorization system. In any key for this car, there is a transponder, nothing more than a "chip" which is picked up by the EIS (electronic ignition switch). If the transponder in the key, and the EIS "agree" (this is decided in a format to lengthy to get into here), then the key will turn in the ignition. To find out if the key is OK, you almost-well, you DO have to get the car to a dealer, don't know any other way. I had time to do just a little poking around in my info at work. The SRS , if a bag-deploying incident takes place, will "shut off" the motor. According to "trusted source", the ME (engine) control unit should be OK with starting again. SRS control module my source believes is still a one-shot deal if a bad deploys. Getting back to DAS, the main components are the key and EIS. The Engine control module may also be considered a part of it, too, as the EIS and engine control also communicate with each other to allow starting, they are both very vehicle specific. The dealer will need to change out the EIS if it is bad. NO one, not even the best independent MB garage, can get access to the materials and authorization to change out the EIS, dealer only. On all other cars except the 220 chassis, the electronic steering lock is also part of DAS. For some odd reason, the 2000 220 chassis didn't have a steering lock, I believe in 2001 it has been changed to be like all the other smartkey cars. On the 2000, I believe that they were counting on the shifter lock on being enough protection, no need to lock the steering wheel also. Seemed dumb to me. On this car, have the airbag/bags gone off? Just curious, was it wrecked, then stripped in a junkyard or what?
Gilly
ps: If it was wrecked, and reported to MB as written off, it is possible MB may no longer "support" the vehicle, that is, not provide a new EIS or keys for it. If you aren't sure, give me the VIN and I can take a look-see.