For Muhoms1: hi, names doug from Lynchburg, Va. my first day registered because I am also having exact same security/no start problem on my 03X. This is a recurring problem, had mine towed to goodyear shop and they had to get solution from Nissan to unlock security system at a $120 cost. Only problem was repair guy told me to call him if I experienced problem again. Now I have same problem, called him and he forgot how he resolved problem. He said he used key (I have no keyfob) in driver door, selecting lock and unlock for some periods of time but couldn't remember after a few months. Ive been trying things for a week with no luck.
He suggested I tow it to Nissan and have them figure out recurring problem. Thought I'd try this forum first before towing and spending $90 for diagnostics and repair time etc. If he just used a regular key in the door lock, it seems to me it would be a rather simple repeatable process to duplicate and one which should be in the owners manual under security system for a stock Nissan security system (not aftermarket), but I also can't find any solution in the manual or on the net to work. Anyone else have suggestions for Muhoms1 and myself? doug.