Q: Check engine light came on and code was P0410

A P0410 can be a real bear on a Mercedes. But first you need to check the simple stuff. The Auxiliary air system is an emission control device that blows air into the hot exhaust stream to help burn up any residual hydrocarbon. (unburned gas) The car decides if the system is working by watching the change in the oxygen sensor when the system is activated. If the change isn’t there, it will decide that the Air System isn’t working. Check all of the hoses and connections including the air diverter valve and all the vacuum lines that are under the hood. Check also the One way valves that are screwed into the cylinder heads to be sure they aren’t frozen up. If all these pieces are working, there is even a possibility that the passages in the cylinder heads are jammed up with carbon, in which case the cylinder heads have to come off to be cleaned out. don’t leap to any conclusions without getting some professional help. Contact Your Mechanic about having a technician come to your home or office and check out Your Air injection and tell you what needs to be done. As for trying to run the monitors, if the fuel tank is nearly full or nearly empty, the EVAP monitor may not run. Make sure that the fuel level is around 1/2 tank.