Comes attached to the pedal ???? What edited by admin thought that up ???

Must be calibrated TO the pedal, but really, this is one of the stupidest things I have ever heard of yet !!!!

At least you do not need a scan tool or programming of the ECM, although we do not have the BENCH stuff on the APPS and the go pedal. It looks pretty straight-forwardly attached, like a one-position mounting. So WHY could it not just be removed and replaced with the go-pedal in place and calibrated? Smells kind of fishy to me.

While in college I worked in an instrumentation lab for a few years, my job was to calibrate stuff similar to this. Almost all of this kind of stuff required a simple bug lite with a battery, once you reached the right position the light lit. It COULD be something just as simple here. I hope someone with some tech info chimes in and let us know the low-down.

CD

 

Mabey I can help shed some light, in my day job I deal with simular items. First off I am a forklift mechanic working on electric lifts, pallet jacks and such. A lot of things I work on are simular to our trucks or vice versa, vehicle managers (ECM's) and other inteligent devices interacting and communicating with each other, Buss signals ect.

As you have already deduced the APPS in its simplest form is just a potentiometer (pot) but I would not be suprised to find out that it is not your standard analog pot but rather an electric pot or probrably a digital pot.

For those that don't know an analog pot is like the dimmer switch on your living room wall to dim your lights with. A POT is nothing more than a manualy adjustable resistor. These are prone to wearing out with normal use because they have moving and wearing parts, you can imagine how fast it would wear out if it was used as an APPS.

An electronic pot does the same job as an analog pot but with no wearable parts and can use inductive sensors to change the output value, in short its a little electronic board with sensors mounted on it and a magnet on the end of the pedel shaft that passes by the sensors and the board varies the signal based off the sensor or pick up being triggered.

A digital pot converts voltage to resistance using a comparitor circuit. This link explanes pretty good. Probrably what our trucks use http://www.elecdesign.com/Articles/A...8055/8055.html

Why would it wear then? simple, electronic parts break down and fail with time, heat (from normal use) and just tolerances that the parts are built to.(it only takes 1 diode or resistor or transistor on the board to fail for the whole thing to act up)

I'm sure the computer monitors the output from the APPS to vary the engine speed and it probrable communicates to it on the BUSS line, heck if you disconnected it the truck may or may not start and idle, at the varry least it should code out indicating the APPS has some problem.

So why make the APPS part of the peddel assy? It ensures that if you do need to replace it, it will be set correctley and you will be able to just install and go. Electronic pots require that an input voltage be present to adjust and set the board, more than just hooking up an OHM meter and adjusting the resistance and locking the pot down. Not to mention probrably ensuring that the BUSS system is working and will communicate with the rest of the truck, and Digital pots are beyond the scope of alot or most of us.

Now I have not traced out the schematic so mabey I am wrong, but if modern forklifts have computers or managers that can be flashed to enable features and programed, and configured then mabey I'm not to far off with whats going on in our trucks.

sorry this is so long
Roddney

 

The programming involved basically re-learns the ecm to the new values. As stated above, there are tolerances to every part and one can be slightly different than another. The proggramming simply tells the ECM that the part has been replaced and this is the new min and max for this part. That way if max for the old part was 4.9 volts and the new part's max is 4.7 volts, you ( the driver ) would feel a noticeable difference in power. There is no real majic to it.

 

Hmmm, towing on a long hill and the engine hesitated. Let up on throttle and power resumed. Check engine light came on. Truck ran fine the rest of the way home but light stayed on. Next morning CEL came on but went off later in the day. Dealer said it was the throttle position sensor on my '06? Didn't have one so I drove truck over the week end and brought it in Monday and they said they replaced it? Truck ran fine during time they said it needed to be replaced and has run fine since they said they replaced it? Now, it sounds like the truck doesn't even have one???

 

I can tell you without any doubt it does have one. As to what one person may call it to another, the term Chrysler uses is Accelerator Pedal Position Sensor. They are not hard to change, and your dealer may have ordered it overnight to have in stock when you took your truck in. Not everything is a conspiracy theory!

 

what are the symptoms of a bad apps..my truck has no idea what my foot is doing lately..surges,drops,surges again ..up and down like surrey girls panties???