APPS, is this right? Big Blue's directions.

cummins724

BREAKING $HIT
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Apr 16, 2007
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I have been throwing a P0121 code for the last month that has no effect on power output. No check engine light, but code is present. I reset my APPs tonight, but here is the deal.

I checked the white tag on the back of the sensor & it said .667vdc. I changed this sensor last summer & kept the old one, it says .595vdc. I checked voltage at the orange/blue tracer wire going to the pcm & got .05vdc. I adjusted my APPS until it read a voltage of .667vdc on the light blue wire going into the APPS & then checked the wire at the pcm again & .667vdc is a match. Did I do it right? Just making sure.
 
Sounds good to me. I still argue that the APPS wire goes into the ECM on the block not the PCM and have no idea how the voltage gets over there but everyone says that is where to check it. I think you did good. Have you cleared the code and gave it time to come back?

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 ***

• 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.



This is my problem with checking the voltage at the PCM. How does it get there????

8W-30-30.jpg
 
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Yeah, I cleared the codes & took it for a ride. They aren't back yet & the pedal is alot smoother feeling now. I hope it is fixed, time will tell.
 
I forgot to say that the orange wire with blue tracer did change as I adjusted the APPS. I don't know how either, but it is correct.
 
I will be switching my sensor when I get home from this place (Maine) sometime this weekend. I will have to do this same deal. I have a dead spot in mine at 20% throttle. Glad you got it fixed. :D
 
I forgot to say that the orange wire with blue tracer did change as I adjusted the APPS. I don't know how either, but it is correct.

how long did the reset take...ive had that code throwing CELs a ton of times and its really annoying. ive been to busy lately to play around with it
 
how long did the reset take...ive had that code throwing CELs a ton of times and its really annoying. ive been to busy lately to play around with it

About 30 minutes because I had to find backprobes, but really about 10 minutes.
 
I will be switching my sensor when I get home from this place (Maine) sometime this weekend. I will have to do this same deal. I have a dead spot in mine at 20% throttle. Glad you got it fixed. :D

There is a thread over on TDR saying that guys found a replacement TPS which works. It is also way cheaper.
 
are u talking about the thread where the dude used crazy electrical jargain and made his own??

My friend told me there is a guy who did that, but he also said that there is another part # that is working, I'll have to check it out.
 
My friend told me there is a guy who did that, but he also said that there is another part # that is working, I'll have to check it out.

yea check it out and let me know what you find cuz i dont think ive ever seen anything else
 
yea check it out and let me know what you find cuz i dont think ive ever seen anything else

I just looked all over & I think he is full of it. I think he just saw where it says "direct replacement" & didn't read it. The only thing I saw was the Williams pedal assembly.
 
I got the number of a guy from TDR that builds his own replacement sensor. I'm gonna go ahead and get it for mine because my APPS was adjusted all the way forward over a year ago and I still couldn't quite get the correct voltage and I know time hasn't improved it any. It's $150.
 
I got the number of a guy from TDR that builds his own replacement sensor. I'm gonna go ahead and get it for mine because my APPS was adjusted all the way forward over a year ago and I still couldn't quite get the correct voltage and I know time hasn't improved it any. It's $150.

Yeah, but we are looking for more of a replacement sensor rather than one that you'd have to hack up a harness to make work. The only one I found on TDR required you to modify your factory harness, I'm not messing with that.
 
This one doesn't. It replaces the sensor and plugs into the factory harness. Let me see if I can't find it.
 
That must be the one he is talking about. I couldn't find it anywhere though.
 
williams apps

I've been running Timbo's apps for 3000 miles now....a nice piece! Plug and play...........Brad
 
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