My Service Engine soon light came on Yesterday. Took my Blazer to Pep Boys to get the code for the issue. Mechanic there told me and showed me the code P0410 Secondary Air Injection system. I checked the fuse, was fine. Started the engine and felt for air coming out of the hose and the pump is working. Is there a sensor that could have gone bad? any help would be awesome.
Dm0n

 

Follow the flow chart in this thread, it will pinpoint the problem. Do each step in order, don't skip any steps unless instructed to do so.

https://blazerforum.com/forum/diagno...plained-35146/

11 pages of flow charts, not a fun one to troubleshoot.

 

It seems like a lot but when compared to the cost of having someone else do the work, it's not bad. Thank you.

 

I wonder if the thermostat would throw this code as well. Just replaced it because my truck was running at a temp of around 160 for the past 2 months and last night my heater wouldn't work. Changed the thermostat and now my heater is working and engine is running at normal operating temp. can i hope for 3 problems fixed???? hopefully.

 

160F coolant temperature should have set DTC P0128, (low coolant temp). The PCM is programmed to set it after a certain amount of run time if coolant temp does not reach 167F as measured at the ECT sensor. Might be a problem with the ECT or its circuits, but extremely doubtful it would be related to the P0410.