i had an 03 t+c van. there is a way to check the codes by cycling the key a certain way or number of times (been a few years). the codes will show up on the odometer.
mine would stall out, like someone shut the key off, at random times. all lights worked, radio etc. everything but starter and ignition. it got worse and worse, sometimes taking a day or more before restarting. no one could figure it out.
i finally put two brain cells together and did the key dance while it wouldn't start. absolutely nothing showed on the odometer as far as codes, even the all is well code. i took a chance that the pcm wasn't communicating properly, replaced it and all was well again.