I need help to find out exactly what's causing this code. Any ideas? Thanks.

 

Sorry, I forgot, 48RE 2006 5.9L 4x4 93k miles.

 

Diagnostic flow chart maybe of some help. Most likely the throttle valve actuator, but check the wiring also for any water intrusion into the connector.

 

Thank you Big Iron, I've changed the TTVA motor and checked the wiring but the the code is still there and the truck is running up to 2500 rpm before is shifting in the second gear. Maybe I've got a bad ttva motor again but I bought it new.

 

there are two calibration tests that I usually run after replacing the actuator. Possible those tests need to be ran to calibrate new actuator to PCM. If you think you have a bad actuator may want to try this test first.