Highly doubt you get get the answers you are looking for or even a timely response. Check out g m t n a t i o n . c o m (no spaces). The members there should be able to help you out.My chevy 2009 trailblazer V6 had the check engine light appear a few weeks ago. Code came up P2440. I replaced the Secondary Air Check Valve (ACD # 214-2151) and reset the computer. The check engine light went away and the car ran great for about a week. The check engine light reappeared with the same P2440 code (Secondary Air Injection System shut-off valve stuck open). There is noticeable deficit with engine performance as well as dimming of interior lights with brake use. The part was correctly installed. Is there anything that could cause the valve to malfunction (i.e. electrical/computer/fuse). I've also read on other forums that the secondary air pump could throw the same code but is unlikely. Could my P2440 problem be linked to dimming light problem? Help?