A picture of a wrench appears on the instrument cluster. Under electronic throttle control, the book says illuminates when the engine has defaulted to a "limp home"operation. Does anyone know what that means?

 

what is the year and engine size of the truck?

 

Whenever the vehicle computer gets a reading from a sensor that is obviously wrong, it will "assume" a value that it "knows will work". On the earliest computer controlled cars with feedback carburetors, if the computer got bad readings from sensors, it would run the carb at the richest setting. You would get horrible gas mileage, but the car WOULD run. The computer would then turn on an amber "CHECK ENGINE" light. It would also store a trouble code in its memory telling what sensor was giving a "bogus" reading.


The newer computers are much more sophisticated, and just because a "CHECK ENGINE" light comes on doesn't really mean the computer is totally in a "limp home mode". Depending on what sensor reading is out of specs the computer may still be doing a pretty good job of controlling the engine. For example, some cars can have the "CHECK ENGINE" light come on if you don't tighten your gas cap tight enough after filling up!
On most vehicles the "CHECK ENGINE" light will go out if the sensor starts giving normal readings again, although some computers will make you use a scan tool to turn the light off.

 

2005 f-350/6.0 l

 

Electronic throttle control is a throttle body setup that is operated by small motor, commanded by the computer. Also known as throttle by wire. You press the accelerator and the computer tells the throttle body to respond accordingly. The primary advantages of this setup are smoother throttle engagements (which can protect the engine from the heavy footed driver and provide better fuel economy), elimination of a seperate cruise control module/motor, and prevent throttle hanging from linkage binding.

The message you are receiving indicates there is some issue with the main computer communicating with the throttle unit.

Try disconnecting the battery for about 30 mins then reconnect. If the problem returns, take it to the dealer