Hello All,

I have encountered kind of an interesting situation trying to help out a friend of mine. He has a '99 2500, automatic, 4x4, dodge. Of course it's cummins truck. He has been having problems with his APPS for a while now. This weekend it finally died on him. I wasn't aware that the actual sensor is detactchable from the rest of the mechanism. So, what I am wondering is if anyone knows the part number or manufacturer of the actual sensor. It looks like any other TPS. Which leads me to believe that it should be interchangable with a like part. The one problem I see with replacing just the sensor is that it requires resetting the baseline voltage and/or resistance. I have done this with other vehicles by rotating the sensor while a multi meter is attached, then locking down the sensor when the correct voltage or resistance is seen. I assume that this technique can be applied to the APPS. So, what I would also like to know is if anyone has information regarding what the voltage or resistance should be at 0% throttle and 100% throttle. Any help would be greatly appreciated, and I will most definately post my results and findings. I think this has the potential to save a lot of people some money, and pain if they understand some fundamental electrical concepts. Thank you, as always...

Sean Daley

 

If you'll do a search, I think you will find a couple of threads on APPS re cal. I think some have done it successfully and others have blown their ECM.

 

If the ECM is going bad, What symtoms does the truck have, rough running, bad Idle? Does it run at all?

Gene

 

... The ECM is fine in this case, so I'm not all that concerned about elimating it as a cause of the dead pedal. Crobtex, I did a search for "APPS re cal" (and about 6 variants getting at the same idea) and found nothing where people have actually physically replaced just the sensor. Do you know any of the specifics behind these people destroying their ECM's? For example, do you know if they altered the wiring to the sensor, or used an imcompatible sensor? Since the only thing a TPS does is varies resistance, thereby varying output voltage, I can't see how it could damage the ECM. Provided, of course, that the wiring is still correct. I'm still looking for a reasonable replacement sensor, and will post my findings, if any. I am still interested in finding out what the allowable readings are for setting the new senosr. Thanks as always...

Sean

 

Check out this thread and see if it helps.

APPS Thread

 

...No that really doesn't get at what I am looking for. I know about the "APPS Reset", and have done it before. Maybe I'm not being entirely clear here. The assembly that houses the cables and the sensor, that attaches to the IP has been removed. On that assembly there is a TPS looking sensor. It is dead. There is no change in readings, either resistance or voltage, when the rotor on the sensor is turned. So, the sensor is completely shot. I assume that it has a failed open as the resistance has gone to infinity. What I want to do is replace just the sensor, and physically set the new sensor's position on the assembly. But because I don't have working sensor to start with I don't have a reference point to set the new sensor. So, I don't need to know to how to calibrate the APPS as a whole, I just need to know how to set the TPS in relation to the APPS assembly. Provided of course that I can find the new sensor. Does help to clear up what I am asking? Thank you, as always...

Sean

 

the dtt site has the info u are looking for.

 

They used to. Now you need some sort of password to access certain files ... that being one! I received the info. from them when I purchased my noise filter. I have the instructions saved as a word document. PM me with your email address and I'll send it to you.

 

Well, it sounds like I have the information I need on it's way. I do intend to do a full write up on my procedure, as I feel it could really benefit the cummins owners that frequent this site. I am looking into doing somehting that has some pictures and shows the tools that are needed to accomplish the job. It should be interesting, and informative. Thanks as usual...

Sean

 

I am in the same boat. Phox could you PM me that info as well. Mine is acting funny at about 1800-2000RPM. Like there is a dead spot in the TPS. I am going to test it with a mutimeter to see how constant the change in resistance is. I could use the reset instructions as well.(not the battery dissconnect wait and reconnect). I have read it on here befor I'm sure but man is there a lot of stuff about APPS on this web site.

 

I think you meant Piperca, as I am info-less.


phox

 

It would be nice to find just the TPS part of the APPS unit as it wouldn't take much to calibrate that unit and I am sure it would cost alot less than the 500 bucks that seems to be the average for these units.


Jason

 

I read some where that certain older trucks you could replace the sensor
but at least on my 2001 you couldn't had to buy the whole thing $330.

 

Mine is dying. I can do the battery disconnect and it will allow my trans to shift fine until I shut off the ignition, then I'm back to disconnecting the negative again. Can someone e-mail me the info as well?

 

Sean, I think what your looking for is: .455 to 3.8V (this is the low end, but alot of trucks are calibrated at this level) .5 to 4V is workable too. Let us know what you find out.