Engine/Transmission (1998.5 - 2002) Recalibrating the APPS

[rweis]

Well, I had some time this afternoon and printed off Bill K's instructions and jumped in.



Key on (not started) C1 Apps read . 511 volts dc.



Took the Apps off as per instructions, easy to do.



Flipped it over and the tag on the APPS read . 579 volts dc.



Followed instructions, torx 20, rap the torx to loosen the 2 screws (ON THE APPS itself), adjust the APPS until you get the Orange w/dark blue tracer at C1 to read pretty close to what the tag reads. Was about maybe 1/32" or less. Like very very very small amount of rotation.



Tightened APPS down and lost some of the correction from the tightening process. Re-adjusted the APPS a tad high (. 585 volts dc) tightened the APPS down and got . 577 (close enough).



Put the APPS back on and went for a drive.



transmission shifts firmer just like it is suppose to be. The transmission was doing pretty soft shifts.



Procedure works well. I would bet there are several (4 - 5) adjustments left before replacement of the APPS.



Bob Weis



BTW also ordered the APPS spike filter fron DTT. Seems the alternator wiring is in the same harness as the APPS and a weak ground, heavy charging or spikey activity at the alternator can cause the APPS output at C1 to read incorrectly. Spike filter is to prevent that possibility.



Oh, did dielectric grease on C1, C2, C3, while I was over there, can't hurt.

 

[Joe Mc]

Well, I had some time this afternoon and printed off Bill K's instructions and jumped in.

Where'd you get Bill K's instructions? Post a link if you have one, please.

 

[rweis]

The site:

http://www.dieseltrans.com/phpBB/index.php

The text:

RESETTING THE APPS SENSOR.

(ACCELERATOR PEDAL POSITION SENSOR)

2ND GENERATION 24 VALVE TRUCKS ONLY.



LIST OF TOOLS NEEDED



DIGITAL VOLT METER

# 20 TORQUE BIT SOCKET

# 1 PHILLIPS

# 10 MM SOCKET



Proper service and repair procedures are vital to ensure personal safety of those performing the repairs. Standard safety procedures and precautions should be followed at all times to eliminate the personal injury or improper service, which could damage the vehicle or compromise its safety.

Although this material has been prepared with the intent to provide reliable information, no liability is assumed in reliance of this material.



It has come to my attention that a lot of people think by disconnecting & re-connecting the batteries and stepping on the throttle it is going to reset the apps, no, that is not correct. It is impossible to adjust your apps if you do not know where it is supposed to be set at. That is why you need the voltmeter.



This is the procedure I use to re-set 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.



· 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 does not matter, it just has to be accurately written down for later reference.



*** TURN THE IGNITION OFF ON THE TRUCK ***









Resetting the APPS Sensor cont. page 2

(Accelerator Pedal Position Sensor)

2nd generation 24 valve trucks only.



· 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.



The two screws that are holding it are plastic, do not put any downward pressure on them or you will never get them off.



· Un do the 6 - 10 mm headed bolts that hold the bracketry in place.

(DO NOT REMOVE THE CABLES)



You will notice the apps is on the back of the bracketry that you just removed, it is held in place by 2 - 20 bit screws. These screws have a little bit of locktite on them so make sure you have a good socket and gently give a little tap with a hammer before attempting to loosen. 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 adjustment should be.



· After loosening the screws you can rotate the apps both clockwise and counter clockwise to get the adjustment you need.



· The reading you took at the beginning of the process on pin # 23 should match the white tag on your apps, if not adjust accordingly.



End of BK's instructions -------------------------



I also put a small wire loop test port (pierce the orange w/ dark blue wire, strip back about 1/8" insulation, insert a test port wire into the pierced hole, solder into place, cover with protective cover (wire loom) for next time) into the C1 #23 wire so it would be easier next time and I can check it from time to time probably when I change the Scotty II air filter.



Bob Weis