I have a 1992 dodge dakota 3.9 le auto trans, with 99k miles i have had a number of problems i cant seem to find a solution to, I tried to clear the codes yesterday, i first disconnected the ground, turned the ignition switch on for at least 30 seconds or more, and then as a safety measure unhooked the positive and place a jumper between the positive and negative cables, left it that way for a half hour. hooked the cables back up and checked to see if the codes had cleared before i cranked it again, had a 12 which means the battery was unhooked , and i still had a 45, and a 32, 32 being the egr valve, 45 has ten things on it. so my question is why didnt it clear all the codes. any help is appreciated