sl320
 

I have 95 sl320 the engine light came on and the code is P0411 Secondary Air Injection System Incorrect Flow. could someone tell me how to fix the problem.

Hello,
Do you have the electric air pump on your car? Some had electric, some were belt driven off the engine. Anyhow either way there is a problem. What I find most common is the electric air pump failing, or the valve failing. There are two valves above your exhaust manifold, the rear one is your EGR, the front one is your secondary air injection. First thing to do is check the vacuum lines, these run from the valves to the front of the engine over the top near the spark plugs, they are plastic and can break easily. check all those out and make sure they are solid and not leaking, then test the valve that mounts on the front of the engine. It is electric and controls both the EGR and the air input. Then last check the vacuum line from the valve to the intake manifold. If your air pump is operating it is likely your vacuum lines, and be sure to replace them with plastic. I made the mistake of replacing them with rubber ones, but they colapsed causing EGR and secondary air pump codes to hit the computer. Oh also check the valve itself, the one above the exhaust manifold in front. Apply vaccum and you will see it operate, if not that is your problem. If you don't find a problem there let me know, I have the documentation for that engine, cause I have one just like it! 96 SL320! It is a great car! I have 135k on mine now and still going strong!
Brian

In addition to what Brian suggested, do a search on the forum. Your question has been asked before and there is plenty of info. My father's '96 had the same fault code, and after reading through past posts I decided his problem was an oxygen sensor.