Is there any way to check for the codes without having to use a diagnostic machine. It's for a 1995 V6 / 5 speed. After a major tune up saturday. Replaced starter a few vacumm lines decarb the ntake manifold,cleaned the EGR and pipe, replace T. body gasket, Spark plugs "NGK R" and finally the fuel filter. It runs great very smooth, but after 15 miles driving the Cel comes ON. Any help will be appreciated. Thanks.