The other day I had the thermostat replaced on my 2007 Gl450. I drove it home and then next day when driving the CEL came on. I ran the code and it came back with P0410. Its the secondary air injection fault. Could the tech working on thermostat have done something to cause this CEL to come on. What should I check?

 

I've never had this fault on my Mercedes, but fought it for a while with a BMW. The secondary air injection pump is an air pump that forces fresh air into the exhaust during cold start situations. On BMW's this was accomplished by a valve on the exhaust manifold that was vacuum operated. It was very common for the rubber hose that fed vacuum pressure to that valve to either come loose, tear, or become brittle with age. That's the first place I would check. The hose receives pressure via a solenoid, which is very easy to test.

 

 

The same happens to me, I have my thermostat change and the next day got code p0410, what was the solution? You clear it and never went back? Or you went to the mechanic ?