Check engine light on car?

I have a check engine light on my car 2002 ford explorer 4.0, and i hooked up a reader to it and the code is (p0442) evaporative emission control system leak detected… How do i fix the code, like what do i need to do to fix it…

http://www.obd-codes.com/p0442

Start with the gas cap. If that's loose or leaking it will cause that code.

if it's not that, there are other things in the fuel vapour capture system that could have come apart, but that gets more technical. So start with the gas cap, that's the most likely cause.

It usually takes a experienced mechanic to fully diagnose the problem. Reading the code is just a first step in determining the problem.

It could be any of the following:

A non-conforming gas cap (i.e. Not factory/original brand)
A small leak/hole in a fuel vapor hose/tube
Other small leak in EVAP system
Faulty vent o-ring seal
Defective vent valve
Defective purge valve
Defective leak detection pump

A faulty gas cap is an easy thing to fix. For few bucks you can buy a new one and see if that fixes the problem. My guess is that it is one of the other more complex things on the list, but start by inspecting your gas cap or spending a few bucks on a new one.

http://www.obd-codes.com/p0442

You're lucky, you have a scan tool. Turn off the light, tighten the gas cap and drive. If the light comes back on do the same thing again but this time use a new gas cap, you can get one at any parts store for ten bucks.
If the light comes on after that forget about the ten dollars you thought you wasted on the gas cap because from here on out it's going to cost real money to find the leak and almost everyone that does this will want you to try a gas cap first. The best way is with a smoke machine and a smart tech.

http://www.justanswer.com/ford/6iyvr-2002-ford-explorer-code-po442-causes-this.html

You need to diagnose if the leak is because of the carbon canister vent valve, gas cap, bad hose, or a rusted out filler tube.