I googled: 2000 Mercedes-Benz E ESP DEFECTIVE
I recommend you see the many answers. There appears to be a big problem in this situation. You may find in MB site a diagnosis and a "fix" If you figure out what the problem is, and part you need, try Ebay for that part or thefind.com
Wild guess $200 to 300
Question edited for a lot more clarity.Question moved to model category.Sometimes they are just on, and sometimes the SRS will flash. Connect to a pro grade scan tool computer and look for the diagnostic trouble codes associated with the fault status.https://www.google.com/search?q=Mercedes+W169+SrS+system+light+on..
Question edited for a lot more clarity, and add maker.
Question moved to maker category.
These are all function of the Body Control Module. You need an auto electrician with a pro grade scan tool computer and access to factory technical bulletins.
https://www.google.com/search?q=mobile+auto+electrician+near+me
No clues in here.
Immobilizers are designed to prevent what you are needing done. There is no easy way around it. Your best bet is to call a lock smith to cut you a new key and program it to work with your vehicle.