Being that the E320-124 chassis has a diagnostic/memory code system that is easily entered, my first familiarization with the car would be to access these codes.
Go to the archives and check out a DIY tool /procedure and then you will know what you are working with.
These are the last of a Flash Code system and you are in luck as they did away with the easy access after '95. [ after '95 require Scanner ..]
There is also a Built-in LED code access provision under the hood for emission related code retrieval...