I was wrong. I was looking at the CD and misunderstood. It is the OD switch and it wasn't cycled during the test is all that code is for.
Thats what I get for not calling things what they are supposed to be called. I call that switch an OD switch. LOL
TCS threw me for a minute
01 F150 5.4L 4x4 and a 98 Mustang GT vert sitting engineless and without transmission or converter
The OD button on the shifter was not working and I got this code. I fixed the button and it now works perfectly - engaging/disengaging OD when pressed. However, the engine light still comes on after driving over 50 with the same P1780 code. Can anyone give me suggestions on what the cause could be?