Replaced the ignition tumbler in this 97 C230. Now I get instrument warning lights but there is no crank. The battery ground and key transponder were unplugged/disconnected. I thought that 97 was prior to requiring SDS to authorize the key.

I have a 97 C230 and it is equipt with a "chip" built in the key. I had to order one from the dealer and show proof of ownership of the vehicle.

98 ML320
97 C230
95 318ti
92 190E 2.6 Sportline
82 300D Turbo Dsl

* To close out this thread, the battery and transponder ring disconnection before the ign tumbler replacement, with subsequent reconnection after the new tumbler was in, had little to do with the failure-to-crank issue.
* Turns out that the remote hadn't worked for a month. And the worn out key blade would now not fit into the new ignition tumbler. Using the new key (which looks like the old valet keys with their rounded black plastic top) which came with the new tumbler wouldn't crank the engine. If there's a chip in that new key, which the transponder needs to interact with, maybe it needs to be synch'd to the security in the car to work. At this point it's only value is locking/unlocking the car.
* The owner brought me a spare remote, almost as beat-up as the remote which wouldn't work, and the car started right up. I've ordered him a new remote, since it has to serve 3 functions: (infrared) remote lock/unlock the car, mechanically key-turn the ignition tumbler, and interact with the transponder ring to give the immobiliser the appropriate signal so that it sends to the ECU the drive authorization to start the engine. (Did you know that "hot-wiring" the starter to crank the engine, when there is no drive authorization, will not start the engine, despite the fact that the dash lights up and looks ready to go.)
* The main lesson from this exercise is to try as many key/remotes as you have for the car before you look much further.

__________________
ASE Master Tech
Quality Enterprises
Mercedes Svc. & Restoration
Sheridan, IN
317.769.3536