more code issues

[deezl duly]

greetings ,ive been quiet lately cuz ive been enjoying cruising around in the newly resurrected dually.running great, no big problems, just the 78 code, but i know that as soon as i get the heath chip, (which wont be long) i can get by as long as i dont push it. anyway today i was puttin along and the ses light came on. i figured that maybe i was pushin it a bit so no big deal. when i got home, i pulled the codes, and came up with a 63, 65, and the usual 78.checking the archives i see that the 63, and65 are accel pedal position 3 circuit high and pos 3 circuit range fault. my question is.....wtf does it mean? am i gonna be left by the roadside soon? and where do i start in my quest to eliminate these codes?any help is greatly appreciated, thanks in advance for all and any help.:???:

 

[1995yukon65]

You can try pulling the connector and cleaning the contacts to see if that cures it. If not it maybe the APP(the pedal assembly)

 

[deezl duly]

ok ill check that its the first time they came up, and i wasnt sure where to start thx alot

 

[buddy]

The truck will run perfectly fine, no different with 2 out of 3 of the APP sensors, but when it gets down to 1 of 3 then it will start limiting fuel. So with just the 3rd sensor messing up the computer will ignore it and you wont have any problems.

Since voltage was registered high, resistance or ground may have broken down, corrosion or dirt or something would cause more resistance and low voltage, unless it opened the ground circuit. The 5V reference comes into sensor 3 on socket E of the connector, and the ground for it is socket J. You should verify with the key on there is 5V across those pins which will verify that the power and ground are good. If not then the ground is bad.

Then you can measure ohms across pins E and J on the APP, there should be a few thousand ohms there, and then the actual feedback to the PCM goes out on pin K which if you measure ohms from E to K it should varry with pedal position.

The odd thing about sensor 3 is that its ground travels back to the PCM on a different instrument panel connector than all of the other APP lines. All of the others travel on a 10-pin connector and the sensor 3 ground on a different 23 pin connector. So if you find an issue with its ground then that may help your search.