Smog Problems! (Someone Plz Help me!)

I have a 1992 Plymouth Voyager that reads (Maintenance Required) on its engine light that does'nt turn off! I took my vehicle in for its annual smog and the mechanic notified me of a problem with my vans (ppm) reading! He told me that he can fix it with a censor but that it would cost alot of money! http://vwvortex.com/zeroforum_graphics/mad.gif I feel in my heart that he's only trying to take advantage of the fact im a female that lacks car knowledge! http://www.vwvortex.com/vwbb/sly.gif He gave me a paper that reads (Manual Readings Mode) He underline a portion that says/ NO(X).......ppm: My reading was 1,562 and supposively the limit for my vehicle is 762! I need some quick help because now my tags are expired and i still dont know what exactly is needed and i dont want to be taken advantage of! If possible could somebody who knows the name of the censor that is needed or another way to fix this problem help me with the information im in need of! Thank you, Sincerely Irene! http://www.vwvortex.com/vwbb/frown.gif

The only sensor I can think of is the oxygen sensor. It tells the ECU what's in the exhaust stream so it can change the air/fuel mixture. If it goes bad, the check engine light will come on and your fuel economy will go down. They're fairly cheap, but I'm not sure how hard it is to replace it on your vehicle.

I think you can have autozone check your computer for the trouble code. They might be able to tell you if its the oxygen sensor.

maintenance required lights are not emissions related. The light comes on at a set mileage, and is reset by a button on the module. Its a dummy light, basically