Code 12 means direct battery input to PCM was disconnected withing the last 50 key-on cycles. If you disconnected the battery that is what it means.
Listen, I had the same truck and the same problem. I had no code to identify the problem like you. After driving the truck with an scanner connected to the engine, for a split second, my map sensor would drop voltage and the truck would die. Then it would start right back up until it happened again. I would like to tell you to try that, but I can't be 100% sure.
Sunday, May 10th, 2009 AT 1:58 PM