Ok, so I have a 1997 Chevy 2500 LD (6-lug 2WD) Cheyenne with the 5.0L Vortec V8 with the 4-speed auto. It doesn't have a "Check Engine" light on when I went to the vehicle inspection station. Once there, the guy said & printed on the page that it shows *No MIL at key-on/engine-off*. He had to start the truck to attempt to read the computer & it registered a P0141 O2 sensor heated circuit malfunction in Bank 1, Sensor 2. I'll admit, I know the basics about the OBD-2 setup, but I'm wondering if there is a common repair for the trouble code (readout makes it seem like a sensor replacement--simple, maybe not cheap). Also, is there something simple that someone else could have done to disable the MIL at the key-on/engine-off cycle? I know what the k-o/e-o means, because my 2 previous GM cars with OBD-2 could be read without starting the vehicle. I did just buy this truck on Ebay, so this explains how something might not throw a check engine light (someone trying to sell it without raising an issue). I got the truck cheap enough that a minor amount of investment may not hurt me.