Volvo: Diagnostic, smog check, sense car

Question
Dear jason Davila
    I have a 95 850 volvo four door sedan, and i recently took it in for a smog check and didn't pass because of a check engine light. So i took it in to volvo and they wanted to charge me $150 to see what is wrong, i wanted to know if you know what kinds of problems  can occur with a check engine light. the car runs perfect no problems last 5 years i had the car. Another ? do you know how much it might cose ball park, i dont want to put 800 bucks into a car only worth 2 grand. well david thats all i had to ask, thank you so much for helping out your doing a big favor for people like me thanks again!

Answer
Larry,
    Well, a 'check engine' light can mean a myriad of things ranging from ignition to your 02 sensor.  If you need to pass your smog check, you might consider tossin that 150 to Volvo.  They also sell Diagnostic Trouble Code (DTC) clearers for about the same price, if not a little more.  The up side to buying one for yourself is that some are designed for more than one make/model.  Regardless of what exactly set off your engine light, it is in your car's best interest (and your checkbook's) to find and clear it.  I'm sure you've heard before, but the engine light is nothing to scoff at or put off.  As far as ballpark repair costs, you say the car runs fine, I assume you change your oil regularly and do all the other common sense car care procedures, so if anything needs to be done, it 'should' be minor (no promises).  So, I seriously doubt that any repair for a car that runs great would exceed 350. If you feel comfortable playing with greasy car guts, DIY costs would be considerably less, and Volvos are typically easy to work on, depending on what needs to be done.
Also, the engine in your car is what's reffered to as an 'intereference engine', which means if your timing belt breaks, your cylinders will continue to move and bang against your valves causing catastrophic damage.  So if you haven't changed your timing belt since you've owned the vehicle, I would HIGHLY recommend it.
I also found this recall for your car concerning the jack.  Jack may lack sufficient load capacity. If so, device could collapse in use.
Lastly, your car is worth closer to 3 grand, assuming it's in as good condition as you say.  Love your Volvo, and your Volvo will work for you!  Don't underestimate the turbo brick!
JD