If the secondary air injection failure code comes up you shold propably check the air pump fuse. I think it is call the air pump. The fuse is rather big. Sometimes water gets into the air pump and causes it to trip out. the fuse is loacated on the front pasengerside close to the bumper. Some people say that you will know that the fuse is out on the air pump because the hood light goes out. That's not really true in all cases.
It does not have secondary air injection.
secondary air injection system
On the exhaust manifold the small stainless steel tube is attached to secondary air injection valve. This tube can become restricted and clogged with carbon causing a CEL code. It needs to be cleaned out.
There are several ways to fix the secondary air injection system in a 2005 Chevrolet trailblazer. The most common fix is; changing the air filter.
Some GM cars have this code but no secondary air, has it been worked on?
The secondary air system pump is on the driver side below the battery .
it has to do with secondary air injection
Need to know what your question is.
right under the alternator below the air filter
Secondary Air Injection Incorrect Upstream Flow Detected
The vehicle will fail an emissions test.
Secondary Air Injection Valve