Engine/Transmission (1998.5 - 2002) How to clibrate TPS

[Mschevey]

I think I have seen posts on here about a system of keying the ignition and pressing on the throttle to recalibrate it. Does this work for the 01. 5 model trucks? If so, what is the magic combination?



Thanks, Mike Schevey

 

[Gizmo 007]

Here's the magic trick.



1) Unhook the negative leads on the batteries. Then, unhook all three plugs from the PCM (the one behind the air filter).

2) Then let it set for about an hour to completely discharge.

3) Rehook the wires to the PCM, then reconnect your batteries.

4) Turn the key switch to the RUN position. DO NOT START THE ENGINE.

5) Slowly depress the throttle pedal all the way to the floor, then slowly release. Do this 3 times.

6) Start engine.



Calibration is now complete.



Hope it helps!

 

[Mschevey]

Thanks, I will try this when I have some time.



Mike

 

[Ncostello]

Will this work on a 99 (built in late 98)??

 

[JPope]

Why do you have to unhook from PCM? Read this procedure in the past, here and other sites, and never seen this part mentioned, but maybe something new has come up?

 

[Gizmo 007]

Don't know exactly why the PCM has to be unplugged. THe only reason i know, is because when I swapped transmissions, I also had to swap the throttle sensor. I forgot to calibrate it before I started the truck, and could only achieve half throttle. I tried unhooking the batteries for a while, but it still wouldn't calibrate. After unhooking the batteries and PCM, it worked perfectly . Maybe there is something like a capacitor backfeeding to the PCM? I dunno, but that's how I got it to work.

 

[AKDrifter]

So Gizmo, what is the advantage to recalibrating the TPS? Does this reprogram the computer to specific driving habits.

 

[15w40]

APPS calibration according to the 98. 5 shop manual:



Turn key to ON position without starting engine.



Slowly press throttle pedal to the floor and then slowly release.

This step must be done one time to insure accelerator pedal position sensor calibration has been learned by ECM.



There is no mention of disconnecting the batteries or PCM and the procedure stated not to press the throttle more than one time, at least for the 98 model year.



The reason the APPS is calibrated is to insure the ECM knows where idle and full throttle are.



YMMV

 

[Gizmo 007]

15w40, in the 98 manual, does it mention anything about replacing the PCM or ECM? It does in the 2001 manual, just curious.



The 2001 manual has the same instructions, except to repeat the process to ensure full range was achieved.



Drifter, when a controller or the sensor is replaced, the computer is clueless as to what voltage range the throttle sensor uses. In my case, I could only achieve half throttle (2100 RPM) with the pedal on the floor.

 

[Newf Limo]

There is no mention of disconnecting the batteries or PCM and the procedure stated not to press the throttle more than one time, at least for the 98 model year.

15w40 I am in the process of trying to diagnose a possible TPS/APPS problem with my truck. I have the 2000 manual. As far as the recallibration is concerned (in the 2000 manual) This procedure is performed on a newly replaced Apps sensor and the battery cables would have been disconnected as part of the part replacement proceedure. Just a thought.



With my truck, I get the CEL when it is cold at start (10*F down to -26*F) But, the truck runs fine with the CEL on. The CEL cleared eventually. A couple weeks later I get the Power loss to Idle (erratic Accel/Deccel) and the CEL with a "Low Voltage at TPS and no reading on speed sensor codes. I changed the fuel filter, first thing. Still did it. $250 later the dealer says codes are cleared, not sure of the problem, here is your truck, give it a try. We hung around town for a little while (went to dinner) and the truck started doing it again, BUT NO CEL! The service department was closed by the time we got there (for the weekend) and the truck started working right again (under threat of having to stay at the dealer all weekend) and it was fine . . . 'till the next day. minus 26*F, Truck starts and runs fine to work (25 miles) after work 10*F truck starts CEL comes on and truck runs fine all the way home. (I do not plug my truck in, no power available) Way to much snow to get it close enough to the house)



Nothing like having $38,000 worth of transportation you can't trust to take you to the store.



I am assuming the TPS and Apps are one in the same. When I mentioned the APPS to the service writer, he looked at me like I had two heads.

 

[dezeldog]

Does this recalbrition fix the hunting of the trans?? IE that famous surge of 1--200rpm?? TIA



Jim