I helped a friend by offering to change the front shocks and upper arm on this model Benz and I disconnected the computer on the passenger side by the windshield, without undoing the battery. I had to get to the upper arm long bolt. I did the same thing on the driver side and unplugged the 3 connectors from the little box underneath the master cylinder. I put it all back and started the car, on the dash a bunch of lights were on, brake, abs, check engine etc., and the car drove in 1st only so limp mode. I unplugged the battery and tried to reconnect the ECU and the other one next to it with the battery unplugged. Now the car starts and cuts right off. This sucks, I read about it and there are some theories to reset, which I tried but couldn't, there are no codes listed when checking. What the heck can it be? Is there a way to reset the circuit clean. I did unplug the battery a few time to no avail.

 

Checked for spark and pulse and got both