Can't pull code's

Its seems that this F150 does not wanna give up any info.
the data link connector is getting power but it fails to connect to the computer. All fuse's are good and relays too but it doesn't connect. any ideas? Drive's fine no CEL on. I did notice that the Radio would reset it self when i turn on the head lights but that was resolved by replacing the battery it had like 234CCA so it would drag to turn on.
05 F150 crewcab TxEdition 4.6L

PCM might be no bueno. Thats about the only thing I've ever seen no let a scanner pull codes other than a blown fuse.

I'm not certain what protocol the 05 Fords use, but it could be that the code reader does not support that protocol. I believe that the 05s still used the SAE J1850 PWM protocol but don't quote me.

ECU"s are pretty resilient. there's a lot of stuff that can go wrong that would imply a bad ECU. Here's a Link that lists those things:Ford Fuel Injection » No Codes? (http://fordfuelinjection.com/?p=44)