Cap'n, I had a problem similar to yours . . .
and the DTC was "Chrankshaft (L5) sensor". The CE light would come on but the car drove and ran ok.
This is the only problem I've had with my car and, in fact, it was this problem that led me to learn about the electronic control systems in the car. And this led to my Mercedes web page.
It turned out to be the DI module, (Menu #5). The module was FUNCTIONALLY ok but had a bad memory bit in the stored faults memory that said the L5 sensor is bad. Similar to a computer with a bad memory chip.
The DI module was functionally ok (except for the bad memory 'bit'. This then caused the DM module to activate the CE.
All of this info as you can see is probably similar to your problem. If possible, swap your DI module out and I'll bet that will fix the CE!
My fix was to buy a used DI module from a NYC parts yard for $200! A new one lists for $1100.
Regards . . . . JimF
'94 S500 Cpe
Visit my Mercedes Web Page