Hello,
I am new to these forums and I come here with a problem.

For several years I have had an Pioneer DEH-5900ib player installed in 2 cars. The current car I have had for probably a year and it is an 2002 Oldsmobile Alero.

I had it removed from my previous car and installed into my new car right after I purchased my Alero. For a while it has been working just fine, but about a week ago, it started making a static noise no matter what I listen to. Radio, iPod, CD, or even nothing at all it continued to make a constant static sound. The only way to get it to stop was turning off the car, but even after the car was turned off the static would continue to come from the player until several seconds after the car has been turned off. It went away for a day or two, but now it is back and I am wondering what it might be.

Any help anyone? It would be appreciated!

It's pretty much impossible to diagnose from just the symptoms. You may have to take it to a shop where they can remove the stereo and test it "on the bench", or just replace it if that seems more practical/economical.

You'll save money if you remove it yourself, but a car stereo shop might want to try adding a filter and/or running it off a separate battery before completely removing it. (You may want to try similar things yourself.)

I'd say there's probably something wrong inside the CD player.

It could be the car's electrical system, but it's strange that the noise continued after you shut-off the car. But, even with the engine turned-off, there are other things running that could generate noise, and the car's voltage regulator is still running, etc. And, I've had some strange symptoms (but not with the car radio) caused by a weak battery.

If it was a bad connection, the noise would usually "change" when you drive over bumps.