I got this A4 1.8T, 2000 model with low mileage around 48, back in oct.03, BUT since then I have had gaskets changed and heat sensor changed, NOW the check system light comes on, and after getting it checked, it talks about SECONDARY AIR INJECTION SYST? what is it? is it important and how much does it cost? Anybody have any INFO plz let me know,
Thanks a bunch

 

Well, if you have an ATW engine, I can give you an idea. That error (Secondary Air Injection System, Incorrect Flow Detected, 16795) can be a bad combination valve. If the combo valve leaks it lets exhaust into the secondary air system. That exhaust will condensate and that water travel all through the secondary air system. In time that will likely corrode the airpump. That water can be a really big problem in the winter when it freezes. Check that combo valve, if the intake side is black, it's a leaker. Replace it and check that airpump, if the problem has been going on for a while, you may need a new one too. HTH.

 

how much is something like this cost?