there is a new software update that should fix your problem as long as the APP's are OK.

lets simplify what saxonmike just said
yes there are two position sensors in the accelerator sensor (pot)

APP1 and APP2 , these are the high and low range sensors and both are built into the pot/position sensor itself. So dont let that 'having 2 pots' fool you into looking for a second potentiometer/sensor.

The chances are its out of calibration and MAYBE you can recalibrate it and the code will go away.
Most of the time you wind up replacing it anyway so just order a new one and replace it because there is something worn inside it causing it to go 'out of range' triggering the code.

The fault is the APP Position sensors do not track well, intermittent connections to the APP or a defective pedal assy.
Here are the corrective actions;
1. Check the APP connector pins for corrosion.
2. Cycle the pedal several times and check APP1 signal at the SECM (ECM) pin B7.
3. Cycle the pedal several times and check APP2 signal at the SECM (ECM) pin B16

The foot pedal assembly uses two potentiometers to detect foot pedal position. These two signals APP1 and APP2 (accelerator pedal position 1 and 2) are sent directly to the SECM. So your code 69 is telling you that your SECM is getting mixed signals from your potentiometers.
So check your connections at the pedal to wiring harness first, then wiring harness to the SECM, and if connections are clean and tight check pin B7 / B16 at the SECM while cycling the pedal to determine if the pedal assy needs replaced. (You can also check the potentiometers at the pedal connector. Getting to the SECM is easier if you jack up the truck or remove the battery and battery box)
Hope that helps

This code refers to the accelerator pedal position and the sensor,do you have an email to post in your profile???