accel pedal
Continuing the steps, let's see if I can intersperse attached images.
NOTE: The next section refers to changing the potentiometer angular adjustment. It should not be needed, unless the two nuts have come loose, and its position has slipped. Unfortunately, it would be hard to know this without a digital volt-ohm meter. Lacking this thing, leave those nuts alone (you are permitted to tighten them). But how can any proper nerd can survive without such a meter (often available for but $20)?
4) Under the cable connector you disconnected you will see these six pins (first image)
I define those six pins as follows, with the APA in its normal (pedal at bottom) orientation:
1 2
3 4
5 6
There are two separate potentiometers/variable resistors inside the case (you will see those later). Toyota calls them "main" and "sub", and so shall we. Measure the resistance of main between pins 4 and 5. Write down the number of ohms. A value of about 470 ohms would be typical with the pedal not pressed down, and about 2000 ohms with the pedal fully depressed (which you accomplish with the left-hand holding-trick described in the previous post, which puts circular dents in your left forearm).
Measure the resistance of sub between pins 1 and 3. Write down the number of ohms. A value of about 900 ohms would be typical with the pedal not pressed down, and about 2300 ohms with the pedal fully depressed.
If your main and sub resistances are unlike the typical, or if the nuts were initially not tight, or if it looks like the whole assembly has slipped all the way to one end, now is the time to loosen the nuts. The whole thing will slip to one end, because it is spring-loaded. Find the angular position that best matches the typical ranges noted above, and tighten the nuts down in that position.
There is a faint possibility that you have now completely fixed the problem, and need not proceed to cutting etc. I don't know, because I have not received a bunch of failed APAs. People are supposed to be sending me those...
NOTE: All will follow the steps below. Please read them ALL before deciding that you wish to proceed. Once you cut, you are COMMITTED.
It is time to start cutting!
5) Put an abrasive wheel on your Dremel moto-tool, or similar. I have no idea how to open the potentiometer box without such a tool. The (obvious) plastic lip must be cut off, but the box and its lid must not get mangled too badly.
see attached second image:
The lip has been ground away, and after removing little burrs, lift off the lid. Inside it looks like, see attached third image:
Upper thing is the "potentiometer box", with 4 three-fingered contact wipers; and 6 springy gold-colored contacts. Below is the "lid", with 4 curved resistive tracks and 6 contact pads. Now, you know what everything is. Just because the potentiometer box in the image is detached from its APA, does not mean that you should do so. Stay on track...
6) Inspect the three-fingered wipers closely, ideally use a magnifier. If they are clean, fine. If they are dirty, clean them with 70% isopropyl alcohol (drugstore item) on a q-tip.
7) Inspect the springy contacts closely, ideally use a magnifier. This is where I noted a small amount of corrosion. Suggest you CAREFULLY rub each of them with sandpaper, emery board, or similar. Then clean each with alcohol on q-tip.
eight) Having finished with the potentiometer box, proceed to the lid. Wipe each of the curved trackes with q-tip/alcohol. You will probably note "dark substance" transferred to the q-tip. Do not wet-wipe them more than twice; the goal is NOT to remove the conductive plastic material! Finally, wipe the tracks with dry q-tips.
9) With emery board or similar, CAREFULLY rub the surfaces of the six contact pads within the lid. This will make them appear much more silvery and shiny. Goal is just to shine them up, not to remove any chunks. Clean each with alcoholic q-tip, dry each with q-tip. You should have gone through at least a dozen q-tips by now. Done, except for reassembly.
10) Now get out your tubes of epoxy cement. I used JB Weld 5-minute epoxy (car parts store item). Similar should be OK, but not something that takes a long time to harden. Somebody is going to have to hold the lid in place during the hardening, or invent build a holding-and-lid-pressing device that does not get in the way of where the epoxy goes.
11) Now practice what gluing people call "dry-fitting". Put the lid into position and feel it snap into the correct position with your fingertip. Learn what this feels like; you will NEED to achieve it accurately once the epoxy is mixed. If you epoxy the lid into the wrong position, the APA will not work, for sure. I found it very useful to have the ohm meter attached (as described above) to confirm the correct position. I know it's possible to do with just the fingertip feel, but I wish you'd just get the darn meter!
12) Mix the epoxy (following package instructions)! Position the lid correctly with your fingertip! Smear the epoxy over all the area where you ground off the lips. Make sure that the epoxy extends both onto the lid, and part-way down the side of the potentiometer box. Do not get epoxy on the 6 external contact pins, nor anywhere near the 2 angular adjustment bolts or their tracks.
13) Continue to maintain the lid in that perfect position with finger, or with the hold-in-place device you invented and built after reading (10) but before performing (11). Incidentally, this is the best reason for using 5-minute epoxy. Nobody wants to stand there for 2 hours. Realize that the 6 springy contacts inside are trying to lift the lid out of its perfect position, and nothing but your finger prevents that.
14) After the epoxy is hard, remove your finger from the lid. Of course this presumes that the finger is not epoxied in place.
15) Wait as long as the epoxy package says. While you're waiting, try to clean up those 6 (external) contact pins that mate with the cable connector. Probably they are not dirty or corroded, but there is nothing else to do during this interval.
16) Reinstall the APA. Tighten the two 10-mm bolts about as firmly as possible, with your hand 4 inches down the socket wrench handle. That's probably about 15 foot pounds of torque, but no way in heck to get a torque wrench into there. Notice how hard it is to wiggle into the correct position to do all this. This is why Toyota techs charge $50/hr and up.
17) Reconnect the cable connector. Then pull it off and reconnect it again. And again. In effect, your are completing the connector-cleaning process. Might as well do it now; you've already wiggled yourself into position.
Last step) Crawl out. Start the car! You should see no error codes. Depress the pedal (in "P") and the engine speed will increase slightly. Still no error codes! Release the pedal, engine returns to idle speed. Congratulations, you have repaired the APA (probably). Go for a drive. Maybe to the hardware store to buy "epoxy remover" to get that stuff off your fingers.
DAS
PS: the images are all at the bottom, and appear in the reverse order. I did my best, you do the rest. PM me if you want to exchange phone numbers to discuss confusions. If Toyota extended the warranty on this (like on the steering), we would not have to do all this. But I still like them.
