Engine/Transmission (1998.5 - 2002) Apps

[Dallan]

i recently have been having shifting problems with my trans and the guy who rebuilt it said to clean my battery terminals and see if anything changed. i cleaned them and it didnt change. i called him and he said its most likley my APPS (accelerator pedal position sensor) i have never heard of this before but he says its about $600 to replace. is there such a thing as an apps and would it affect the down shifting on my truck or is he trying to screw me? anything will help, thanks

 

[FourBarR]

Yes there is an APPS. Your throttle cable is connected to it rather than directly to the injection pump. Generally when they go they set a code o121 or o122. you will need a code reader for a 99 truck. They are pricy and not that hard to change.

I had to change mine at 350,000 kms.

 

[Dallan]

will an apps cause my trans to act different if it is going bad? how much would it cost to buy one?

 

[rkressg]

An APPS costs about $400 and takes about 1/2 hr to change.

I am not certain if there is any relation between an APPS failure and a transmission shift failure. You could have an issue with a solenoid, torque converter, clutch inside the transmission.

Hopefully someone with more knowledge of the Autos will chime in.

 

[wcaldwell]

I'll pass on the tip given to me (and really all of us here in TDR Land):



1. Disconnect all 4 battery cables.

2. Let the truck sit at least 30 minutes - overnight is better.

3. Clean all battery cable connectors and battery posts.

4. Reconnect batteries.

5. Get in your truck and turn on the ignition - DO NOT START THE TRUCK!!!

6. SLOWLY press the accelerator pedal to the floor.

7. JUST AS SLOWLY release the pedal.

8. Start the truck.



This re-sets/re-programs the APPS and/or computer. I've done this 3 or 4 times and it works great.



Wayne

 

[arlan]

apps reset

The link below is for a reset of the apps. I did not have a problem with shift points however. I had the dead pedal thing going on. You could read the voltage at the #23 pin of the ECM on the C1 connector and see if it is close to 0. 551 VDC. If it is half of that try the below. It is not difficult. I have 700 miles on my truck now with no dead pedal.



I would not have a lot a faith in a transmission guy who told you to check your battery cables. My cables are barely snug. Makes then a lot easier to remove when necessary.



The procedure below comes from Transmission Guru Bill Kondolay of DTT.



Arlan



https://www.turbodieselregister.com...02/186808-dead-pedal-apps-tps-adjustment.html

 

[SHobbs]

Wasn't there a fix for this concering a brown wire close to the alternator? Don't have an auto but, I remember something along those lines, I believe it was a small piece of foil around the wire solved the problem. Try looking into that before you replace the APPS.

 

[Dallan]

thanks ill try these things and get back with you. anything else will help too

 

[SnoKing]

DTT has a electrical noise filter available that also corrects OD hunting most of the times.

SNOKING

 

[Fishin Guide]

A bad APPS can affect shifting. But there are more factors than that as well.



What exactly is your trans doing? No offense but "shifting problems" could be a multitude of things.



With the autos, you could have all the issues listed above and then some. Your trans may just be done too. It's hard to say even with a detailed description, but at least you can get some better ideas before dropping $400.



Dave

 

[Dallan]

fishin guide, when i say shifting problems i mean it takes forever to down shift. also slipps a little when shifting from 1st to 2nd with little throttle

also i dont believe i am experiensing dead pedal but what exactly is it?

 

[Fishin Guide]

fishin guide, when i say shifting problems i mean it takes forever to down shift. also slipps a little when shifting from 1st to 2nd with little throttle

also i dont believe i am experiensing dead pedal but what exactly is it?

Hard to say. I would call ATS if that's who built your trans. My gut says governor solenoid or VB issue. But I am no trans builder!



When mine was doing what you describe, my trans had to be rebuilt. It was internal leakage and the clutches were fried. So, my experience is rather limited.



Dave

 

[BWagnaar]

If you look on the driver's side of the transmission and find the cable running to a lever, that is your T. V. cable (throttle valve), this can affect transmission down shifting and when it upshift too. Follow it up to your throttle housing, it should run into a connector on the housing with a white clip on the side.

Pop that loose and let it come out about 1/8 to 3/16 of an inch. Be careful though cause its spring loaded a little a if you let go it will spring back all the way and you'll have to play with it to get it to shift right.

Letting it come out a little will tighten the cable, this should make it kick down sooner.

By pushing the cable into the connector and throttle housing it would loosen the cable causing it to kick-down later.

I had to play around with the TV cable when i got my new transmission in to get it to shift where i wanted it to.



Good luck

 

[SHull]

Remove the apps wires in the wire bundle that lead to the ECM. It is a major pain but it works.



02 Ext cab

 

[mhenon]

i recently have been having shifting problems with my trans and the guy who rebuilt it said to clean my battery terminals and see if anything changed. i cleaned them and it didnt change. i called him and he said its most likley my APPS (accelerator pedal position sensor) i have never heard of this before but he says its about $600 to replace. is there such a thing as an apps and would it affect the down shifting on my truck or is he trying to screw me? anything will help, thanks

I just bumped the thread "Anatomy of an APPS" to the top. It's a long read but the good stuff starts about page 25 or so.

There is a better fix for your APPS and it's much cheaper too. Hope this helps.

Mike

 

[magaliasram]

I have tried the bypass to pin 23 from the APPS and it didn't help, I tried to reset the voltage on the APPS by checking it at pin 23 and adjusting to the specifications on the back of the APPS it didn't help. Frustrated and ready to give up I did the forum search and came up with a $12. 50 noise filter attached to pin 23 and a ground wire in that harness and the trans has never shifted better with one exception. It has about a 4 second delay when downshifting from overdrive and third I overcame this by simply actuating the overdrive button or manually shifting down from third. If you find you need an APPS there is a thread that has the info for a aftermarket APPS potentiometer that sells for around $160. 00. Just search the forums you will be surprised at what you can find.



Jim