Archived sudden dead pedal-!!!

[RBeard]

Drove a mile away from house and bam, dead pedal/CEL. checked codes and 121,122 showed,limped back home and checked apps voltage. on the money with apps tag. tried pedal reset and still dead pedal... ANYONE have an idea.



Replaced APPS and VP in Dec. (< 1000 miles since) :{:{

 

[mhenon]

Drove a mile away from house and bam, dead pedal/CEL. checked codes and 121,122 showed,limped back home and checked apps voltage. on the money with apps tag. tried pedal reset and still dead pedal... ANYONE have an idea.



Replaced APPS and VP in Dec. (< 1000 miles since) :{:{

That's not good! Sounds like a dead APPS even though you just replaced it. You might go around the vehicle and pull all the grounds, clean them up and make sure they make solid contact with the chassis. this might mean grinding down body paint to get to metal. Also, check all electrical connectors. . especially the ECM/PCM. I pull mine every year and add a little dielectric grease.

Get somebody to clear your codes (like Auto Zone), then disconnect the battery and turn on the lights to drain the capaciters in the system. Reconnect the battery and reset the pedal.

If none of this works you might be looking at a new APPS. Good luck.

Mike

 

[RBeard]

checked voltage on apps, correct voltage at idle stop,3. 82 at WOT stop. that shows me the apps rheostat is working. Would ecm throw a code if it's bad. There is no code # shown on code sheet for bad ecm????

 

[DonFitzwater]

I had one like this last summer and it turned out to be ECM. The only reason I fixed it was due to having a donor truck at the same time and swapped parts until I figured it out. My problem was the same as you. The truck in question had just had a new pump put on prior to having dead pedal experience again.

 

[RBeard]

came home tonite and decided to try the truck again. still dead pedal. unplugged apps and plugged in old apps and it worked. unplugged old apps and plugged in new one and now it works. (I wonder how long. )



Fitz- did you have to replace your ecm to solve the problem.

 

[ceastmen]

Ecm

A friend of mine at work went through the same symptoms your describing and after many trips to the repair shop it turned out to be the ECM.

Chuck E.

 

[RBeard]

Drove 150 miles yesterday with no problems,got in this morning and went 100 feet and DEAD pedal again. Is there any way to test the ECM or do I just replace it (Owch):{

 

[comm-tech]

I'd try the old one again. If the old one works again, then the new one works when reconnected I'd suspect an intermittent in or near the connector. I've been in electronics for quite a while and I've seen more than a few harness connectors where the wire wasn't stripped properly or the terminal not crimped properly.



Karl M.

 

[RBeard]

Good idea,i hadn't thought of that. that might explain the code of low apps voltage

 

[harrisfd]

Deja' Vue!

Wow, I've been experiencing the exact same problem on my 2001! New APPS, same codes, same dead pedal. I'll clean the grounds and check the connectors & let you know if I find anything. Thanks for the info.

 

[rweis]

We have a fix for the APPS Oo.



https://www.turbodieselregister.com...nsmission-1998-5-2002/99611-anatomy-apps.html



Most of the info you are probably interested in occurs in the threads dated 2008 page #6



Bob Weis

 

[RBeard]

Apps

Thanks Bob, the apps is new (less than 1000 miles). what is the reason for adjusting the voltage when installing a new apps. Dodge says they install it,calibrate it(key on,pedal down and up slow,key off) and that's it.

 

[rweis]

The general thought is that if you are having problems that seem APPS related, one possible fix is to get the expected APPS voltage on the sticker that is on the APPS itself and the actual voltage which is measured at pin 23 C3 as close as you can. Close being (a guess) about . 1 volts ie at least . 479 if the sticker is . 579. Generally happens over time.



I do not know what the tolerance is, but if the differences are fairly large (. 3xx at pin 23 C3 vs APPS expected . 579) the APPS can demonstrate failure when it is only not close enough between actual and expected.



I do not know a lot about the APPS, only what I have found out through experimentation. I have a LOT to learn about the APPS and how it interfaces with the ECM.



I "think" the "learn" procedure tells the ECM the low and high end of the APPS potentiometer voltage values.



Bob Weis