Mitsubishi Repair: Lancer 02 Check engine light, voltmeter, autozone

Question
My '02 Lancer Check engine light came on. What do I do? I took it to Autozone to to get a check and he said that the plug used on my car to check was defective (not working). How do I narrow down what is wrong with it, I am scared to go to the mechanic because they seem to always try to take advantage of me.  What can I do?

Answer
Shamekia: Go buy a repair manual for your car at any parts store and get then get a voltmeter, along with the repair manual, you can check starting from the battery through the car, till you find which sensor or sensors are out. Or else go to some other shop and get them to code your car. Some shops have deals on this, they code your car for free and then you pay them for fix whatever is wrong. Up to you, but you will need to get this fixed. Hope this helps and good luck. But also Merry Christmas!