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(I think that's what APPS stands for right? if not correct me and I'll change it)

 

Can someone do a write-up on how to reset or re-learn the APPS? I remember reading about it but didn't pay a lot of attention. I've got a buddy that I think his APPS is going bad and was going to have him try this first.

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Disconnect batteries with key on for 30 minutes.

 

 

Turn key off.....

 

 

Attach batteries. Turn key on.... press pedal SLOWLY to the floor and SLOWLY out three times?????

 

 

 

 

This is the only thing that comes to mind.

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I got this from someone over on DTR quite a while back. Copying the writeup from the word document lost all formatting and fancy stuff (so if something doesn't make sense, that could be why). I can email the original attachment that I was given if anyone is interested.

-Augusta

 

RESETTING THE APPS SENSOR

This is the procedure DTT recommends to reset the APPS:

 

With the key on, engine off, you need to probe the APPS wire to see where your voltage is currently set at.

 

The best location to probe the wire is on the PCM (Power Control Module), which is located off the passenger side of the firewall. There are three plugs going into the PCM. You’ll need to remove the air filter housing to get easy access to it

 

You want the C1 connector; this is the connector closest to the engine

 

You want the orange wire with the dark blue tracer, which is pin #23

 

Voltage should read somewhere around 0.5 volts

 

At this point the voltage reading doesn’t matter, it just has to be accurately written down for later reference

 

TURN THE IGNITION OFF ON THE TRUCK

 

The APPS sensor is located slightly above and a little to the left of the injection pump.

 

Remove the black plastic cover that is located by your injection pump. (Be very careful unscrewing the plastic screws, they strip very easily. Do not apply any downward pressure to the screws)

 

Undo the six 10mm bolts that hold the APPS bracket in place. (Do not remove the cables) You will notice the APPS is on the back of the bracket that you just removed. It is held in place by two 20 bit torques screws. These screws have been installed using Locktite, so be sure to use a good driver bit and gently tap them with a hammer before attempting to loosen them. Be very careful, these screws strip very easily and you only get one shot at them!

 

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, you can rotate the APPS clockwise (increase voltage) or counter-clockwise (decrease voltage) to get the adjustment you need.

 

The reading you took at the PCM (pin #23) should match the voltage on the tag, if not, adjust accordingly.

 

I found that hooking up your multi-meter at the PCM and adjusting the APPS, while monitoring the voltage, worked the easiest. You’ll need to have the key on, engine off, for this. Once you set the voltage to the correct setting, turn the key off to reassemble the APPS bracket and related parts.

 

Good luck!

 

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The manual specs when replacing the APPS, meaning it has been unplugged or replaced, you reconnect the batteries, thurn the key to ON and do not hit start, slowly push the pedal to the floor and return it to idle, turn OFF key.

 

Recalibration complete.

 

This is not the procedure for changing the voltage of the APPS at a given position. That is found on DTT's site.

 

Dave

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Ok, so this leads me to ask this. What would cause me to want to recalibrate the APPS? And what would cause me to want to check/adjust the voltage of the APPS?

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Ok, so this leads me to ask this. What would cause me to want to recalibrate the APPS? And what would cause me to want to check/adjust the voltage of the APPS?

 

 

Recalibration is to solce issues with the PCM/ ECM and the APPS. Typically, some type of electrical interference or drop out gets the confuser out of whack. Recalibrating restores this if only for a time. Aand a temporary fix is the signs of a failing APPS.

 

typically, changing the voltage on the APPS is for the auto guys. It allows the voltage to be raised and the lockup points to be changed.

 

Dave

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Doing the battery disconnect reset is usually just a temporary "fix". According to Chrysler, the PCM has what is called a "block learn memory". This memory is updated depending on how the vehicle is being driven. In other words if you drive like a little old lady, then the pressures controlled by the governor solenoid will be adjusted "slightly". To a small degree this can change shift point, harshness of shifts, etc. When you disconnect the batteries you clear the block learn memory, and it has to relearn. The pressing the throttle to the floor speeds the process of it learning what the WOT voltage is. If there is something wrong (APPS out of adjustment for example), clearing the block learn can help, but usually the symptoms will come back as the block learn re-updates itself. An example of where clearing the block learn can really help, is if the PCM has had bad information supplied to it (for example a bad governor pressure transducer), the learn function may not update itself to the correct information after a new transducer has been installed. Some of the PCM's will only update it's block learn for a certain number of re-starts since the last time it was cleared. In those cases if bad information is stored in during the block learn cycle, it won't be corrected until it's cleared, by disconnecting the batteries.

 

Where I have seen this happen is when I'm drag racing. If I disconnect the batteries long enough to clear the block learn, just before racing, there are small changes on how the truck runs and shifts. It's not much, but when you are trying to be consistent to less then a .01 of a second, every little bit matters.

 

Sorry for the long post...

Paul

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Recalibration is to solce issues with the PCM/ ECM and the APPS. Typically, some type of electrical interference or drop out gets the confuser out of whack. Recalibrating restores this if only for a time. Aand a temporary fix is the signs of a failing APPS.

 

typically, changing the voltage on the APPS is for the auto guys. It allows the voltage to be raised and the lockup points to be changed.

 

Dave

 

So could one get their TC to lock a tad sooner by increasing the voltage?

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So could one get their TC to lock a tad sooner by increasing the voltage?

 

 

Yes.

 

But, there is a point of too much advance on the APPS. Basically, there are a couple of switches insid of it. They tell the computer when the engine is at idle. So, if you advance the APPS too far, the computer won't like it, throw codes and may not start.

 

However, to fix, you just back the voltage down a bit.

 

Dave

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