New to the forum
That fuse is for engine control unit. Might be faulty unit, or wiring issue.
also could be the camshaft sensor:
(post #12) https://mbworld.org/forums/w211-amg/...s-burning.html
(post #13) https://mbworld.org/forums/e-class-w...p0560-obd.html




https://fuse-box.info/mercedes-benz/...uses-and-relay
Fuse 43 powers the ME (Motor Electronics). Disconnect ME module and see if you have a short to chassis on that line. If it is a bad ME, you'll need to source a replacement. That will require either the PROM from your ME transferred into another "re-virginized" ME or the replacement ME being programmed with your vehicle VIN. If replacement is required, you will need STAR/Xentry to "marry" the replacement ME to your vehicle. I've only done this once; not difficult but slightly stressful.
For your sake, I hope it is just a short in the power line and not a problem in the motor electronics.






