13) I tried a few different variations of turning on the Rear Window defrost at start up: Turned on the defroster before start and turned off at the end of the first air pump cycle. Turned on the defroster before start and left it on. Each case the P0410 code would appear.



14) Figuring that the issue may be resolved with additional ground, I added an additional 16 gauge ground wire to the ground terminal of the air pump directly to the negative terminal of the battery. This was done be stripping ½ inch of insulation from the ground wire near the pump (without cutting the original wire) and taping in an additional wire by use of wire clamps. Note the battery is only 2 years old. Still no luck. After a few days of driving, I get the P0410.


I think I’ve run out of ideas. The forum has been a great help giving me tips so far and I thank you, but I fear that this issue might require professional help. Since I live in Ithaca, NY, I am hours away from any Mercedes dealer. Not sure what I will do next.