Check engine light comes on after replacing belt tensioner and serpentine belt. I put a goodyear gator belt and a new belt tensioner on the tahoe, and the next day the check engine light comes on for some reason. I did this to try to isolate a possible whistling/whine type noise that comes on right when I start the engine. Noise goes away after about 5 seconds. Unfortunately changing the belt/tensioner..and noise didn't go away.

I did try to really spot where the noise was coming from, and I think it might be coming from a part from the front of the truck, just to the right of the radiator, which has some kind of hose going towards the engine. It has an in and out in which one hose is attatched to the in, and just a small piece of hose is connected to the out. Any idea what this is, or what the noise I'm experiencing might be. I do notice that when this noise starts that part does seem to vibrate a lot, and stops vibrating when the noise goes away. I'm not sure what part that is exactly however. Is it some kind of pump?

 

Is it the PS pump?

Need to get the codes scanned.