Paul, yes this was discussed recently and the fix was a matter of timing. Did you find the recent post on this?
Originally Posted by ftuhy View Post
I found one thing omitted in various threads on this topic, so here's how I successfully reset the FSS for Service A on our 2001 SLK320
1. The hood must be open, or at least unlatched
2. Get in the car and close the doors.
3. Wait for the dome light to go out. (Not sure this is necessary; I haven't tried to skip this step.)
4. Insert key and turn to position 2 -> idiot lights come on, engine not running
5. Push button 1 (trip odometer) twice quickly -> the time/distance remaining for FSS is shown.
6. Push and hold in button 1.
7. Turn ignition key back to off position, still holding button 1 in.
8. Turn key back to position 2 while still holding button 1 in.
9. Continue holding button 1 in; within 10 seconds you'll hear a beep and 10000 will be displayed again.
10. You can now release button 1. FSS has been reset.
I went crazy following steps 2 - 9 with no success, then decided to open the hood (step 1) and repeat the process. Finally, success!!!
The hood part did it. I did everything by the manual, which does not mention raising the hood. Worked 1st try , Thanks Frank