Throttle actuator control (TAC) system Error

  • 2005 FORD F-150
V8 four wheel drive automatic 54,557 miles.

My 5.4 liter will enter a forced idle mode while I am driving. This has happened three times in the past forty six miles (one hundred and twenty five minutes of running time). There is no common time that this happens ie: cold and wet or dry and warm. I pull over turn the truck off and then it starts rough but does start each time. The truck does run fine other than this. The vehicle displays three error codes, P2104 TAC - forced Idle Mode, P2111 TAC - stuck closed, P2111 TAC - stuck open. Ford does not recommend cleaning the throttle body. With that amount of miles on the vehicle I do not think I should have to replace the whole throttle body. I was thinking maybe the throttle body sensor? If you feel it is one of these two items how hard are they to replace?
Do you
have the same problem?
Thursday, January 1st, 2009 AT 3:33 PM

1 Reply

Okay, first off ignore the P2104 as it is being set because of the P2111 code okay. Now this code is set because there is a problem with the TAC motor. So there is either a problem with the throttle body itself as it is stuck open or something or there is a harness problem to the TAC motor or there is a problem with the PCM. With a digital multi meter we can run some tests. Now first things first this is an easy test manually check if the throttle moves freely with the engine off is yes then we go to the next test. If it does not move freely buy hand then check the throttle cable and the throttle body for any problems visually.
Now visually check the TAC motor harness for any visual problems if all looks good and the wiring looks like there is no fraying or anything then we go the next step.
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Friday, January 2nd, 2009 AT 10:49 AM

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