Check codes (key on-off-on-off-on rapidly WITHOUT trying to start it). Count flashes of the check engine light. There will be a longer pause between digits and all codes are two-digit. You will probably see a "12" first and a "55" at the end. "12" is loss of battery within a certain number of starts (50 or something) and "55" is end of codes. Lots of palces on the net to find the codes, but the best I've found is http://minimopar.knizefamily.net/.