Starter problems of the 2006 Buick Lacrosse

For years, going back to when it had a warranty and the dealership even worked on it for this problem and has had one or two calls in the years since for same problem, ses light comes on, it used to go off and on occassionally, but now has been on for a year or so constantly. It is for diagnostic code p2440 (secondary air injection valve stuck open). Dealership replaced valve and/or air pump years ago and said it would fix it, but it didn't. Within a few weeks, ses light came on again for same thing. I called them and they said I could bring it back, but it would be on my dime because they barely got it covered the first time under warranty. We put up with it for a bit, then I purchased a new valve and installed it myself, light did not go out and it still to this day says the valve (new one even) is stuck open. Problem is, when the ses light is on, the remote starter won't work, which is very upsetting for me and my wife. For years, just like the first problem listed, it was initially “fixed” while under warranty, which only worked for a short time. The passenger front seat air bag sensor has a mind of it's own! sometimes it registers a person, sometimes not. It doesn't even matter what time of year it is, or the temperature in the car. Sometimes it thinks that my wife (160 lbs) is a child and doesn't turn the air bag on and then if we hit a bump (sometimes works) then it might turn it on. It also has times that it also turns on the red air bag light on the dash while it says off for the passenger seat air bag. Years ago when we took it to the dealership for this problem, they said they “fixed it” initially, but it was just a short time later it did it again. When I called the dealership to let them know, they said just like the problem listed above, that it was out of warranty now and that I'd have to pay out of pocket, so I didn't take it in.