Purchased a hail damaged 2006 Ford F250 5.4 from a salvage yard. Knew there would be some work to do, but given what I paid...anyway, one thing that I cannot fix is the check engine light problem. The codes are P0340 & P0344. Had the cam sensors replaced, and even replaced the alternator (which was OK, but did it anyway) and still get the check engine light.

I sort of checked the wiring harness, but not quite sure if I can spot damage or if there is a short. The TSB for these codes says to replace the alternator because of bad diodes or rectifier. Like I said, I replaced anyway although the O-scope test showed the diodes and rectifier were OK. The bulletin says to reprogram the PCM if the diodes are OK. The Ford dealer said that if they did that the check engine light would still come on....? The dealer did clear the code w/ an OBD scanner, but the check engine light came right back on. So, I am thinking of resetting adaptive memory. Not sure what else to do?

One thing of note: I found a service invoice on the seat dated before the insurance company took title and before the truck was put it into the yard. The problem then was the check engine light. Nothing was done, so this problem had been going on for awhile. The truck runs great, but this light is driving me crazy! Any suggestions would be greatly appreciated.