Accelerator pedal position sensor DIY fix in 2005 Quest

[far raf]

About 4 months ago my 2005 Quest lost power and would not rev up for the first time. Back then I removed the TPPS (aka APPS) plug, re-inserted and the engine worked fine ever since. 2 days ago it did the same thing and only after removing and re-inserting the plug 3 times it worked... for 5 minutes. Repeated the procedure about 6 more times and was able to get home (a 20 min driving distance) without issues.

I removed the entire accelerator pedal assembly from the power pedal unit (requires removing the dashboard lower plastic panel, lower metal shield and unscrewing the light bulb housing from the metal shield). The 3 bolts that hold the pedal have very tight nuts and it was very difficult to remove. Also the threaded portion is very long and it was exhausting for the fingers to undo the nuts all the way. I grinded the excess of the threads off and chased the nuts with the 6mm tap, they are very smooth and easy now.

As you can see in the pictures of the APPS on the Web, it has a cover which seems to be held in place by the molten tips of about a dozen of prongs. It is not so! The dimples on the cover is plastic injected into the holes which is supposed to seal them. The cover is glued to the case along the perimeter. I carefully pried the cover off with a narrow wood chisel (watch your hands!) and it exposed a white teflon PCB with 4 variable resistors. The plug pins are connected to the PCB with short pieces of wire soldered on both ends. I re-soldered the joints with good quality lead based solder and used conifer rosin for the flux. Then I checked resistivity from the pins as in the FSM diagram and it read the correct values. Previously one of the resistors read open circuit:

4 3 2 1
o o o o
o o o o
8 7 6 5

4 and 3 have a connection with 6
8 and 7 have a connection with 2
1 is missing in mine.

I did not bother gluing the cover back to the case, as the 3 screws will hold the cover in place very firmly anyway. When assembling, I reversed the direction of the top and bottom front (facing the cabin) bolts, and left the bottom rear (facing the engine bay) screws. The bottom rear has to be cap to the left nut to the right as otherwise the bolt would interfere with the power pedal bracket. The reversed bolts are much easier to remove as without dropping the nuts into the bottom of dashboard in this tight space.

Hoping that helps anyone whose Quest throws the APPS/TPPS codes P0222 and P0223 (hope I got these right). I did this repair not because I am cheap and did not want to spend $70 on a reman pedal, but because I had to get it done very quickly. It only took me about 1 1/2 hours from start to finish and I had to take a road trip after that. But still saving a few bucks feels good.