I have a 2008 Trailblazer with about 100,000 miles. I got a P0411 code a couple of weeks ago. I replaced the secondary air induction valve, air pump and relay. I reset code and disconnected battery for an hour. It worked great for a week and now I have a P2440. P2440 code means that the air induction valve is stuck open. Any ideas what would cause the P2440? Thanks in advance.