The wife called me from out of town last week saying her 91 740 was "squealing" like a hog when she turned the steering wheel either way. Turned out that one of the mounting bolts in the PS pump (the most inaccessable one of course) has apparently worked itself loose and fallen out. After trying to tighten the belt with out success, I finally noted the missing bolt and replaced it after which the tensioner tightned up the belt nicely. While I was messing with it, I decided to go ahead and drain the system of the old fluid that looked like chocolate milk and do a refill with Mobil 1 ATF. I flushed the system plus the rack with 2 quarts of regular ATF fluid and let it drain overnight and instilled the Mobil 1 in the morning. It acts like a new system, quiet and smooth as silk. The problem is I now have a check engine light on with a code 1-2-2 being displayed with the pigtail in the # 2 (fuel system) socket. According to my book, this is an "air temperature sensor" fault. Anyone know what and where this sensor is? The engine starts and runs fine as if nothing is wrong with just this yellow light glareing at you. I imagine I have knocked off a wire somewhere in my fiddleing around but no luck in finding it. Any help appreciated.