I'm getting A p2431 I have replaced the air Check Valve any other suggestions that I may check out 08 trailblazer 2.4

 

Remember, a DTC (in this case P2431) DOES NOT SAY that this part or that part is bad. A DTC is telling you there is a problem with a particular circuit or system, and serves as a starting point for diagnosing what is wrong.

I suggest you read this regarding the Secondary AIR Injection System:

https://www.obd-codes.com/p2431

Good Luck!