2003 Suburban 5.3l engine... P1516 code is the only code showing... Any suggestions?

I have seen the P1516 on 2003-2006 GM vehicle equipped with a 4.8 5.3 6.0 or 7.0 V-8 Engine and every time it was a different tune.

If I have to put it into perspective: For every GM vehicle went through our shops (Two) for code P1516, if we line all of 'em up from bumper to bumper: The line would be stretched from Texas to Michigan, that was how many vehicle: Fixed or not: Sometime the owner just want the vehicle back because want to go to the dealer, back from the dealer to our shops, or the trade in took place for another vehicle, lack of fund for the repair, pissed off because we've kept the vehicle for so long, national back order for the needed part/ component, trade it in for another vehicle etc and etc (You name the reasons and all are corrected)

'Nuff' said for the BS. P1516: The definition for the code as a whole is something like this:

DTC P1516 set, key in crank or run mode, system voltage over 5.23v, not in Battery Saver Mode, then the ETC or TAC module received a signal that the Actual and Commanded throttle positions were not within a calibrated range of each other, or that the PCM and ETC or TAC module could not determine throttle position, or that both TP signals were invalid, condition met for 1 second.

Vahoooo ! Throw in the TB (Throttle Body: Expensive guess) should take care of it. Right? WRONG!

The following causes were the most common ones:

1- The Throttle Actuator Control (TAC) / throttle body type trouble code, may be caused by a loose wiring crimp at the throttle body connector, or a broken throttle body circuit.

2- Charging system is at fault: Don't let the description "Scare" you, I've seen a battery cable terminal or high resistance (Corrosion) was the cause (Let's say): Beside the common causes like alternator or battery.

3- Grounds: Grounds for related circuit: Best way is to do the voltage drop or "Scope" the ground to find out.

4- Slices in the circuit: Been overlooked by the technicians due to the Flat rate system (?): My guessing as an onwer (ESO)... or by not fully understanding how CAN/ BUS in a vehicle communication take place among controllers (Vehicle's computers)

5- The Tach module rendered useless due to defect in the charging system..

6- The left side cylinder head was removed for any reason and upon reinstalling: Ground problem occur.

7- The irregular (Hi and Lo voltage supply to the Underhood Bussed Electrical Center (UBEC)

8- A defected ignition switch.

9- An after market (Dorman) PCM

10- Replacement part such as PCM is DOA (Dead On Arrival), sometime even came from GM, left alone Dorman unit (After market). Haft of the time PCM was not the cause until power, signal or ground have been verified.

11- Human errors (That would be my technicians)

Sorry for the long and confusing answer (If it did not help you at all). But if you still having questions or need more helps then email to me at: Liverhuyen2003@Yahoo.com

Otherwise: Don't forget to close the question. Thank you.

The Throttle Actuator Control (TAC) / throttle body type trouble codes, may be caused by a loose wiring crimp at the throttle body connector, or a broken throttle body circuit.