1994 s600 mercedes benz coupe, when i start the car the pressure rises to 95 then it drops to zero after turning off the car or keeping the key on without starting it. what could be wrong. the car will start but shut off after 3 minutes of running and will not restartts

SOURCE: 1995 Mercedes Benz C220 will not start, and key

hello,steering lock mechanism and your key need to replaced,if you want try to remove your under dash,steering lock mechanism have a small pin(around 5 mm) which pit to steering housing,drill out the lock,then try to turn steering wheel,ty

SOURCE: Air Conditioning on 2001 Mercedes-Benz CLK

You could remove fuse 25 (30amp) in the underhood fuse panel, but then no blower for AC, heat, or defrost. Need to replace blower regulator.

SOURCE: My 1994 Mercedes Benz SL500 radio display turns on, but no sound?

I had same problem with my 1994 SL600. Also when this happens you will lose your interior door lights when you open the doors. My problem was solved by taking out the, A-white 40 amp 12V Relay and cleaning off the 6-prongs and reinstalling. It is located in the box underhood ahead of the main fuse box. Just need a phillips screwdriver. It is the fartherest relay in back left. I had to pull the one out in front of it to be able to remove the white one. You can hear it click when you push in dooropen switch. When working right you do not hear it. Hope this helps.

SOURCE: My 2000 Mercedes Benz S500 is dead- electronic key does not

It's not that unusual for a battery to fail that soon, and the "no lights, no nothing" says that it's the battery again. Your best bet at this point is to pull the battery and take it to the point of purchase for testing. They should either replace it under warranty or charge it for you. After you replace the battery you should have the charging/electrical system checked for possible shorts or power drains.
BillB

SOURCE: how to reset airbag for mercedes benz c220 1994

This can not be reset by conventional methods. This must be done through a scan tool. Usually only the dealer scan tool will communicate with the SRS module. If the SRS light is on you have other issues and they must be remedied before the light will go out. There is no way of knowing what the issue is without running codes with the scan tool.