98.5-02 Cummins 24V 5.9L VP-44 Tech Talk Tech Articles for the 2nd Generation Cummins 24V 5.9L VP-44 Engines.

Adjusting APPS

 
Old Aug 26, 2008 | 03:23 AM
  #1  
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Default Adjusting APPS

Instructions:

Tools: Digital Volt Meter, T-20 Torx bit, #1 phillips, 10mm socket

With the key on, engine off you need to probe the APPS wire to see where the voltage is currently set at.
The best location to probe the wire is on the PCM (Power Control Module) which is located on the passenger firewall behind the air intake.
You want the C1 connector, this is the connector closest to the engine
You want the orange wire with a dark blue tracer which is pin #23
Voltage should be somewhere around 0.5 volts,
At this point the voltage reading does not matter, it just has to be accurately written down for later reference
TURN THE IGNITION OFF ON THE TRUCK

Remove the black plastic cover off of your APPS. There are two plastic screws. One on the top and one on the front facing the radiator. It takes a little prying to pull it off.

Undo the 6-10mm bolts that hold the bracketru in place but DO NOT REMOVE THE CABLES!!

You will notice the APPS is on the back of the bracketry that you just removed, it is held in place by 2-T20 torx bit screws. These screws have a little bit of locktite on them so make sure you have a good socket and gently give a little tap with a hammer before attempting to loosen. Be very careful because these screws strip VERY easily and you only get one shot at them (VERY VERY VERY IMPORTANT; They are VERY tight).

On the APPS you will find a white tag that gives you the information on what the APPS voltage should be.
After loosening the screws (do not remove) you can rotate the APPS clockwise or counter clockwise to get the adjustment (towards the front of the truck increases voltage and towards the rear of the truck decreases voltage)
The reading you took at the beginning of the process on pin #23 should match the white tag on your APPS. If it doesn't the adjust accordingly.
 
Old Aug 26, 2008 | 06:37 AM
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Hey nice write up Luke
Nothing else going on @3:23 am. Your work is done, go get some sleep
 
Old Aug 26, 2008 | 01:54 PM
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I did this on mine and the tag said .595 volts but the sensor would only roll up to .48volts so i talked to a service guy at cummins southern plains and they said you can't adjust your apps which makes no sense because i just did.
 
Old Aug 26, 2008 | 02:42 PM
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Originally Posted by Jazz
Hey nice write up Luke
Nothing else going on @3:23 am. Your work is done, go get some sleep
Not my write up found it on another Forum last night just thought I would post it here.

---AutoMerged DoublePost---

Originally Posted by cummins24
I did this on mine and the tag said .595 volts but the sensor would only roll up to .48volts so i talked to a service guy at cummins southern plains and they said you can't adjust your apps which makes no sense because i just did.

Did you try rotating it forward a few times? They dont want you to fix the APPS they want you to buy a $300+ new one.
 

Last edited by Diesel Dawgs Performance; Aug 26, 2008 at 02:42 PM. Reason: Automerged Doublepost
Old Mar 14, 2009 | 12:49 PM
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what part are you actually rotating forward? I can't seem to get mine to rotate more than just a few degrees

---AutoMerged DoublePost---

Never mind I guess its just those few degrees that make the adjustment. I got it up to .74 I guess its going to be touchy getting it close to .585

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I've got some pictures to add to this thread when I'm done. This really isn't that hard to do.

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I was able to get it to .60, I probably could have gotten it to .58 or .59 but the Bruins started at 1 and it took such a small amount of movement to change the reading that I could've been doing it all day to get it just right.

It turns out my wire had a retard clip on it so it was pretty easy to take a reading.



Here's what it looks like after the cover is off and the bolts are out.



This is the APPS on the back side of the bracket.



And a close up of the white tag on the back.

 

Last edited by jesse; Mar 14, 2009 at 12:49 PM. Reason: Automerged Doublepost
Old Mar 14, 2009 | 02:28 PM
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Hows the truck run?
 
Old Mar 14, 2009 | 03:34 PM
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so should i re adjust my apps with a new VP cause after heavy fueling to like dies then revs back up?
 
Old Mar 14, 2009 | 03:50 PM
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this should be made into a sticky...thanks for the post
 
Old Mar 15, 2009 | 10:01 AM
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Originally Posted by lukesdiesel
Hows the truck run?
I didn't really notice much of a difference. Should there have been a noticeable difference? What does the APPS do?
 
Old Mar 22, 2009 | 10:24 AM
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Becareful gang... This adjustment of the APPS is not suggested on older wore out APPS sensors... There is a few things here in the proceedure that no one is taking anout. Like idle validation switches and the state of them, the fact you measuring the signal at the PCM< when it should be at the ECM. The PCM controls the cruise control the ECM controls the fueling...

I run in a few that have done it and other sub system quit working like exhaust brakes, high idle to name a few quickly...

I've even updated my APPS page of this information...
APPS Sensor
 

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