Engine/Transmission (1998.5 - 2002) APPS reset

[JCyrbok]

could someone refreash my memory on the procedure to reset APPS? Think it is key to on, slowly up and down on pedal 3 times will do it? Or do batteries have to be disconnected first?



Been driving real conservative last 2k or so doing mileage "testing" and I think the ECM "learned" my habits. Want to reset to see if there is a difference.



Thanks

J-

 

[pwr2tow]

Disconnect batteries for at least 30 minutes, then reconnect batteries, then key to on position do not attempt to start, then push peddle down slowly to floor then back up slowly, do this three times, then turn key off, then turn back on and start your engine.



Ron

 

[rblomquist]

Didn't realize you had to do it 3 times. I did mine once months ago when I first got the truck and heard about this procedure; results were awesome.

 

[V6power87]

What is the APPS? What does it help by reseting it?





Thanks.

 

[monkfarm]

APPS

Yeah! Don't keep it a secret! What is APPS???

 

[JCyrbok]

APPS

Its the ACCERLATOR PEDAL POSITION SENSOR. The ECM on our trucks ( I belive auto only) "learns" your driving habits over the course of as little as 500 miles. The ECM then recalibrates the APPS in line with your habits so that WOT for you may not actually be WOT for the truck. Reseting the APPS will allow full use of the throttle range. This is atleast how I understand it. Someone chime in if I'm off base with this.



BTW both the positive and negative connections or just positive?



Thanks

J-

 

[pwr2tow]

both the negatives should be sufficient, but it doesn't hurt to disconnect the positive too, would be a good time to clean the terminals and apply a little anti-corrosive to them.



Ron

 

[ihegdal]

I received a copy of the Windows based "Car Code OBD-II" software recently. One of the data screens gives a real time readout of the APPS signal in % (TPS %). I thought I was in need of a APPS calibration after seeing that with no pressure on the pedal (engine not running) the readout was showing ~ 10% and at WOT the reading was ~70%.



My truck is a 2001 w/auto, the 2001 service manual APPS calibration say's to slowly press the pedal down 1 time, this thread is indicating cycle the pedal down three times. Does anybody know if the procedure is different for different model years?



I tried both procedures ( with a 30 minute battery disconnect each time). I eventually ended up with the closed throttle setting at 45% and the WOT setting at 70%. This was something of a problem when I started the engine. Shut engine down as rpm went past 2,000.



The only way ( the last thing I tried) to get back to where it was to start with was to pull the connector of the APPS, cycle the ignition. This did give a 0% APPS reading on the "CAR Code" Software screen, plus a DTC. Turned off ignition , plugged APPS back in. Turned on ignition and checked with software again, CT was ~10% and WOT was ~ 70%. Does anybody know if these are normal readings for a 2001 w/auto?



Truck is operating normally at this time.



Ian

 

[pwr2tow]

Originally posted by ihegdal

I tried both procedures ( with a 30 minute battery disconnect each time). I eventually ended up with the closed throttle setting at 45% and the WOT setting at 70%. This was something of a problem when I started the engine. Shut engine down as rpm went past 2,000.

I have never heard of this happening before, maybe someone has and will give more information on this.



The way I read it is you said you tried both procedures and they both netted over 2,000 rpm upon startup. Seems to me there is something else going on that could create this, what I do not know.



Ron