I've seen references to this procedure here and elsewhere. There is a step-by-step description of it given in message 149714 in this forum (link: https://www.dieseltruckresource.com/...9714#msg149714).

My question is - what does this procedure actually do and under what conditions would one execute it, i.e. to solve what kinds of problems.

Don in Portland

 

dkinzer - I used that procedure when my '99 would hunt between OD & drive @ about 40 mph under light acceleration. Most of the roads around here are either 35 mph or 40 mph and the truck would constantly shift up & down. The procedure worked but only temporary in my case as I had a bad ground which I eventually found.

Hope that helps.

 

From what ive seen it's usually performed when either ..1) the shift points are off in a automatic....2) trans starts out in 2nd gear instead of 1st....3) The Torque converter is locking and unlocking repeatedly...their may be more reasons but these seem to be the most common....

 

The procedure reteaches the "gas pedal" it's limits.
There is no longer a mechanical connection between the pedal and the engine, it is "fly by wire", computer controlled.

Think of it as kinda like the controller for a slot car, or a joystick on your playstation.

Sometimes it gets confused and forgets where it's start and finish are.

Or it will get a dead spot midway through the travel.

Recalibrating it reteaches it where bottom and top are, and makes it ignore the dead spots.


phox

 

Thanks for the information.

I posted a message here a while back about what I thought was a strange shifting behavior on my truck. I've since concluded what I'm actually observing is the lock/unlock of the torque converter.

Going along at 35MPH on a level surface, pressing the accelerator slightly results in a drop in engine RPM (which I now believe to be evidence that the TC clutch locked at that point). Backing off slightly results in an increase in engine RPM (when the TC clutch unlocks, I believe).

I'm going to try the APPS recalibration and see if this changes at all.

Don in Portland, OR

 

are you driving around town (30-50 MPH ) in overdrive? and what size gears do you have?

 

I usually don't turn OD off unless I'm towing and/or operating in hilly terrain. The axles are 3.55.

Don in Portland, OR

 

At 35 mph the torque converter is locking up alright but in 3 rd gear not overdrive. I dont think shutting the over drive off makes much difference at this point unless the shift points in the tranny are changed when the over drive is off which from what I have seen there not.

By the way my truck has done the same thing from day 1.


Jason

 

[quote author=Scubasteve link=board=4;threadid=20926;start=0#msg196530 date=1066101073]
At 35 mph the torque converter is locking up alright but in 3 rd gear not overdrive. I dont think shutting the over drive off makes much difference at this point unless the shift points in the tranny are changed when the over drive is off which from what I have seen there not.

By the way my truck has done the same thing from day 1.


Jason
[/quote]

Jason, the tc lock up will only occur in the highest gear that's allowed. If you allow OD the TC won't lock up in 3rd (d). That's for stock electronics. With a stock TC you won't note much of a difference whether you are in D or OD at low speeds. With my stock TC I had lower rpm if drove OD off and the TC locked @ 35 mph than in od with the TC open.

Just my 2c

AlpineRAM

 

The link to the procedure in this post no longer works. Anybody have it?

 

APPS Reset Procedure

Wow, what an old thread. I think you dug up an old post from when DTR used YaBB SE for the forum software before the upgrade to vBulletin. Thats why the old link no longer works.