Engine/Transmission (1998.5 - 2002) Anatomy of an APPS

[Gary - K7GLD]

I might make one appeal here, to guys reading all this, and who have used/failed APPS and/or APPS brackets they don't plan to use, and just haven't tossed out yet...



There is still experimenting and refining to be done here, and the contributions made by a few onlookers in supplying test units is EXACTLY what got us where we are today! I, personally, would NOT have had the success and testing I have done , if it wasn't for the several TDR members who have contributed their otherwise useless parts for experimentation.



If there are still other APPS modules and brackets out there not serving any useful purpose, consider offering them to any of the guys here who are involved in testing - it sure would be appreciated!



And, TIA!

 

[mhenon]

Gary, I have my OEM bellcrank assembly (with Williams APPS I installed) sold locally. What I have remaining are the mounting bracket (the aluminum casting that actually bolts to the manifold) and two "dead" OEM APPS. Just so everyone knows. . one of these dead APPS was donated by TDR member Scott Lauer. None of this would have been possible without members like Scott making whatever contributions thay could. PM me if you need any of this.

Mike

 

[JLandry]

John, Are you going to install the Williams APPS any time soon? I'ed like to know how it works for you. The more folks testing this stuff the better. Keep in touch.

mike

Mike,



I'm waiting for a combination of free time and good weather (since I have to work on the truck in the driveway) on a weekend to do the conversion and testing. Since my OEM APPS is working perfectly, and I haven't been able to locate a spare dead APPS for a bench top setup, I'll have to disassemble my OEM unit to accept the Williams sensor. While I hate to disassemble a perfectly functioning OEM APPS, I will if I have to in the interest of science.



Prior to disassembly and the associated loss of calibration, I plan to take resistance readings of the OEM APPS at idle and WOT (while on my workbench) so I can attempt to duplicate the same readings with the Williams sensor once installed on the OEM bracket. My line of reasoning is this:



It would be easier to take simple resistance measurements using a good digital Ohmmeter versus having to take voltage readings with the APPS on the truck or even on the workbench using a 5. 0 volt power supply. I think they both should yield the same calibration results. If this method is possible, it would make swapping out a dead OEM sensor with a Williams sensor while on the side of the road a lot easier (if the resistance values are known before the OEM sensor dies).



But then maybe I'm just trying to be different and making things more confusing... dunno.



Another thing no one has yet commented on is how the Van Hool Service Service Bulletin No. 1103 (referenced much earlier in this thread) instructs the installer of a replacement Williams sensor to repeat the APPS "learn" procedure three times. I'm wondering if this is the answer to preventing the initial "transplant rejection" DTC's some have experienced with a new APPS and different calibration from the original?

"The ECM and accelerator pedal must be calibrated when an accelerator pedal is initially installed, when an accelerator pedal is replaced, when a new calibration is downloaded to the ECM, and when the accelerator pedal wiring is being disconnected while the vehicle ignition switch is ON.



To recalibrate the ECM and accelerator pedal, the ignition switch must be in the ON position and then the accelerator pedal must be slowly and fully depressed from idle to full throttle.



Repeat the procedure three times. "​

I'm not sure if this means you press the accelerator pedal to the floor three times in a row without interruption, or you have to shut off the ignition switch in between, etc. It seems worth trying though.



If anyone has a dead APPS assembly from an auto transmission equipped 2nd Gen 24V truck which I can buy for a reasonable price to cover your hassles of packing and the shipping costs, PLEASE PM me!



Thanks,



John L.

 

[rweis]

Mike,



Prior to disassembly and the associated loss of calibration, I plan to take resistance readings of the OEM APPS at idle and WOT (while on my workbench) so I can attempt to duplicate the same readings with the Williams sensor once installed on the OEM bracket. My line of reasoning is this:



It would be easier to take simple resistance measurements using a good digital Ohmmeter versus having to take voltage readings with the APPS on the truck or even on the workbench using a 5. 0 volt power supply. I think they both should yield the same calibration results. If this method is possible, it would make swapping out a dead OEM sensor with a Williams sensor while on the side of the road a lot easier (if the resistance values are known before the OEM sensor dies).



... .....



Another thing no one has yet commented on is how the Van Hool Service Service Bulletin No. 1103 (referenced much earlier in this thread) instructs the installer of a replacement Williams sensor to repeat the APPS "learn" procedure three times. I'm wondering if this is the answer to preventing the initial "transplant rejection" DTC's some have experienced with a new APPS and different calibration from the original?

"The ECM and accelerator pedal must be calibrated when an accelerator pedal is initially installed, when an accelerator pedal is replaced, when a new calibration is downloaded to the ECM, and when the accelerator pedal wiring is being disconnected while the vehicle ignition switch is ON.



To recalibrate the ECM and accelerator pedal, the ignition switch must be in the ON position and then the accelerator pedal must be slowly and fully depressed from idle to full throttle.



Repeat the procedure three times. "​

I'm not sure if this means you press the accelerator pedal to the floor three times in a row without interruption, or you have to shut off the ignition switch in between, etc. It seems worth trying though.



... ... .

What I have observed about the "re-learn" process.



I do not know more than I know about this process. When I went to the bus APPS from the OEM APPS I tried to do everything I could think of to get the "new" readings into the ECM. SUDDENLY (and for no apparent reason) the ECM "learned" the new bus APPS. Why?, I have no idea. There is more to this "re-learn" than meets the eye.



I (the ECM) finally learned the bus APPS. All was fine.



I changed to the MS IVS and guess what?, yep 0121 voltage readings do not agree and it will not allow engine acceleration. Changed back to the bus APPS IVS and fine. Back to the MS IVS not fine. I did NOT change the APPS pot, just the IVS signal. So there is more to it than JUST the APPS pot value, because I did not change the pot, only the IVS from the bus IVS circuit to the MS switch.



I have tried the 1 time vs 3 times "learn" process, did not recalibrate the ECM values.



Now, what will get the job done to reset the ECM APPS (& IVS) values? I do not know. There IS a key, I do not know what though. There is a key because my ECM eventually did the "re-learn".



Bob Weis

 

[mhenon]

Mike,



I'm waiting for a combination of free time and good weather (since I have to work on the truck in the driveway) on a weekend to do the conversion and testing. Since my OEM APPS is working perfectly, and I haven't been able to locate a spare dead APPS for a bench top setup, I'll have to disassemble my OEM unit to accept the Williams sensor. While I hate to disassemble a perfectly functioning OEM APPS, I will if I have to in the interest of science.



Prior to disassembly and the associated loss of calibration, I plan to take resistance readings of the OEM APPS at idle and WOT (while on my workbench) so I can attempt to duplicate the same readings with the Williams sensor once installed on the OEM bracket. My line of reasoning is this:



It would be easier to take simple resistance measurements using a good digital Ohmmeter versus having to take voltage readings with the APPS on the truck or even on the workbench using a 5. 0 volt power supply. I think they both should yield the same calibration results. If this method is possible, it would make swapping out a dead OEM sensor with a Williams sensor while on the side of the road a lot easier (if the resistance values are known before the OEM sensor dies).



But then maybe I'm just trying to be different and making things more confusing... dunno.



Another thing no one has yet commented on is how the Van Hool Service Service Bulletin No. 1103 (referenced much earlier in this thread) instructs the installer of a replacement Williams sensor to repeat the APPS "learn" procedure three times. I'm wondering if this is the answer to preventing the initial "transplant rejection" DTC's some have experienced with a new APPS and different calibration from the original?

"The ECM and accelerator pedal must be calibrated when an accelerator pedal is initially installed, when an accelerator pedal is replaced, when a new calibration is downloaded to the ECM, and when the accelerator pedal wiring is being disconnected while the vehicle ignition switch is ON.



To recalibrate the ECM and accelerator pedal, the ignition switch must be in the ON position and then the accelerator pedal must be slowly and fully depressed from idle to full throttle.



Repeat the procedure three times. "​

I'm not sure if this means you press the accelerator pedal to the floor three times in a row without interruption, or you have to shut off the ignition switch in between, etc. It seems worth trying though.



If anyone has a dead APPS assembly from an auto transmission equipped 2nd Gen 24V truck which I can buy for a reasonable price to cover your hassles of packing and the shipping costs, PLEASE PM me!



Thanks,



John L.

John, as to removal and install of the APPS/Bellcrank assembly it's really a piece of cake. You can leave the black plastic cover off while you're making adjustments and corrections. A 3/8" ratchet and 10mm socket are all that's needed to remove the bellcrank assembly to get at the APPS. Everything else can stay in place while you remove or mount a new APPs sensor.

The voltage reading at pin #23 on the PCM are all that's needed to make idle adjustments. Both Bob and myself tapped the wire on pin #23 and soldered a pigtail on it to facilitate taking these voltage readings. I didn't like the idea of continually piercing that wire.

As to recalibration of the new APPS I've done it several ways all with the same results;

1. I've done nothing and just let the ECM learn on the go which worked on both OEM APPS and Williams APPS (I forgot to calibrate but it ran fine).

2. I've done the "key on. . pedal to the floor. . key off" one time (ran fine).

3. I've done the "key on. . pedal to the floor and back 3 times. . key off" (ran fine)

I wasn't sure either what the VanHool instructions wanted and did it the way I described. As far as resistence readings there is plenty of info on this thread as to what various members came up with on their different APPS. I never took a resistence reading from either of my Williams APPS (Bob did) but both have similar (almost identical) voltage values at pin #23. I've now tested two different Williams APPS on my engine, the one on the Williams pedal assembly and a spare that I tried first on the OEM bellcrank, and they both worked fine.

Mike

 

[JLandry]

I changed to the MS IVS and guess what?, yep 0121 voltage readings do not agree and it will not allow engine acceleration. Changed back to the bus APPS IVS and fine. Back to the MS IVS not fine. I did NOT change the APPS pot, just the IVS signal. So there is more to it than JUST the APPS pot value, because I did not change the pot, only the IVS from the bus IVS circuit to the MS switch.

Bob,



That's weird!



Wasn't there discussion some time back on the correct "logic" for the IVS circuit being validated... i. e. which pin(s) should be grounded upon validation versus open upon validation? Are you sure have all that set up correctly?



John L.

 

[JLandry]

As to recalibration of the new APPS I've done it several ways all with the same results;

1. I've done nothing and just let the ECM learn on the go which worked on both OEM APPS and Williams APPS (I forgot to calibrate but it ran fine).

2. I've done the "key on. . pedal to the floor. . key off" one time (ran fine).

3. I've done the "key on. . pedal to the floor and back 3 times. . key off" (ran fine)

Wow!



For whatever reason your particular setup sounds very forgiving. You've been able to pretty much just slap a new Williams sensor in place of the OEM sensor and then go. That's the best scenario anyone could ever hope for when their OEM APPS goes TU leaving them stranded on the side of the road.



I think I'll go ahead and solder in a pigtail to pin 23's wire just like you guys did so I can take those voltage readings for comparison. Dumb question: Where do you ground to?



Thanks,



John L.

 

[Gary - K7GLD]

WELL, just for additional info and data, I only did the "depress the pedal" bit one time after installing my own APPS version - no problems. But I also carefully duplicated all items of resistance, so the replacement "looked" like the original to the ECM...

 

[mhenon]

Don't forget to unplug that PCM connector before soldering. Wouldn't want any heat or voltage of any kind getting into the PCM. Look for a ground coming right off the PCM going to the firewall. I unscrewed that ground wire, sanded the paint off the firewall to get a really good ground and added another pigtail there for the ground probe. Chassis ground is what I've been using.

Mike

 

[timbo]

I think the IVS contacts should be reversed from what you're describing. From tracing the APPS schematic and from testing Rick's APPS I think the idle contact should be between between pins 6 & 1, and the off-idle contact between pins 2 & 1.



From the 2001 manual the schematic on page 8W-30-30 shows both contacts closed, not the usual normally-open and normally-closed contacts. This is confusing to me. The contact that goes to pin 6 is labeled "1" and the contact that goes to pin 2 is labeled "2". Then there's wording along side that says

1 idle

2 not idle

I'm thinking from this that contact #1 (which goes to pin 6) should be closed at idle, and contact #2 (which goes to pin 2) should be closed when not idling.



What do you guys think? Mike, when you get a chance what about reversing the contacts and see what happens?



It's possible the ECM doesn't throw a code and run it back to idle until it sees a TPS vs IVS discrepancy a few times, to avoid false alarms.

Karl was absolutely correct on this one ! When i did the Ford TPS EXPERIMENT on the mustang throttle body i accidentlly got 1+ 6 closed at idle an 1+2 closes at accel. Just so happened i got them reversed the CORRECT way. The shematic diagram shows it in the IDLE position!! When i wired my finished Ford APPS i just went off the way the MS. was wired on the throttle body EXPERIMENT, i never looked at the diagram after that.

I just went out and TRIPLE checked the MS. wiring and 1+6 are connected at idle and 1+2 are connected OFF idle. I AM VERY SORRY FOR ACCIDENTALLY MIXING THIS UP!!!!!!

 

[Gary - K7GLD]

Gary, I have my OEM bellcrank assembly (with Williams APPS I installed) sold locally. What I have remaining are the mounting bracket (the aluminum casting that actually bolts to the manifold) and two "dead" OEM APPS. Just so everyone knows. . one of these dead APPS was donated by TDR member Scott Lauer. None of this would have been possible without members like Scott making whatever contributions thay could. PM me if you need any of this.

Mike

Thanks for the offer Mike - and Scott was the one who sent me the bracket I used for the setup I am now running on my truck - very much appreciated, for sure!



What I'll be looking for, is another complete bracket, with or without the actual APPS module - I still have one extra of those left for testing. I'd like to make up another complete MS setup, using what was *thought* to be a "failed" APPS, along with a MS for the IVS function, and see if that returns the "failed" APPS to proper service.



THEN, I'd wait until someone here is having APPS problems, and is willing to be a Beta tester for what I make up - we need as many test setups running as possible, and we can only run one at a time! :-laf



At the moment, the only "spare" bracket I have, is the one removed from my truck to install the test setup, and naturally, I prefer to keep that one un-molested, just in case! :-laf



SO, if anyone has a complete, and unneeded APPS bracket gathering dust. I'd sure like to get one!

 

[timbo]

Karl was absolutely correct on this one ! When i did the Ford TPS EXPERIMENT on the mustang throttle body i accidentlly got 1+ 6 closed at idle an 1+2 closes at accel. Just so happened i got them reversed the CORRECT way. The shematic diagram shows it in the IDLE position!! When i wired my finished Ford APPS i just went off the way the MS. was wired on the throttle body EXPERIMENT, i never looked at the diagram after that.

I just went out and TRIPLE checked the MS. wiring and 1+6 are connected at idle and 1+2 are connected OFF idle. I AM VERY SORRY FOR ACCIDENTALLY MIXING THIS UP!!!!!!

Gary, can you double check yours?

 

[Gary - K7GLD]

Gary, can you double check yours?

I sorta hated to muddy the water on this one! :-laf



I used the DC schematic posted earlier in this thread:



(NOTE! Theoriginal schematic posted here was WRONG - here's the correct one



#ad




As can be seen, closing 1 & 6 provides the Idle Validation signal, and closing 1 & 2 provides the OFF-idle validation signal. Mine's wired that way (I'm pretty sure... ), and works perfectly.

 

[timbo]

I sorta hated to muddy the water on this one! :-laf



I used the DC schematic posted earlier in this thread:



#ad




As can be seen, closing 1 & 2 provides the Idle Validation signal, and closing 1 & 6 provides the OFF-idle validation signal. Mine's wired that way (I'm pretty sure... ), and works perfectly.

Now that is SUPER WEIRD!! I just went out and pulled the wedge out of the duetz 6 PIN and switched #2 and #6 wires and plugged it in. I then did the relearn process and I didn't get the petal 1/2 way and the CEL light popped on. I then plugged the smarty in, and guess what code 121! After that, I cleared the codes and switched 2 and 6, and plugged it back in. Again I did the learn process and all is fine, NO CEL light.



Bob, try switching #2 and #6!!



NOTE, I tested this on my set-up with the Mustang TPS and MS, because i just sent the Williams set-up to Brad Patterson. He is the first one to get the set-up,because he sent me his extra bellcrank assembly. I'm still amazed he second dayed it to me from florida, ON HIM! THANKS AGAIN BRAD!

 

[Gary - K7GLD]

Now that is SUPER WEIRD!! I just went out and pulled the wedge out of the duetz 6 PIN and switched #2 and #6 wires and plugged it in. I then did the relearn process and I didn't get the petal 1/2 way and the CEL light popped on. I then plugged the smarty in, and guess what code 121! After that, I cleared the codes and switched 2 and 6, and plugged it back in. Again I did the learn process and all is fine, NO CEL light.



Bob, try switching #2 and #6!!

NOTE, I tested this on my set-up with the Mustang TPS and MS, because i just sent the Williams set-up to Brad Patterson. He is the first one to get the set-up,because he sent me his extra bellcrank assembly. I'm still amazed he second dayed it to me from florida, ON HIM! THANKS AGAIN BRAD!

WELL, old age and failing memory CAN be treacherous! :-laf



I hesitated to dive into this, because I'm going on memory, and what I *think* is right... I'll verify that as soon as my duetz plugs arrive, and I can get my other OEM setup hooked back up in the truck, and verify the wiring - so don't get TOO excited on my statements yet! :-laf

 

[mhenon]

That schematic looks different then mine. The one I have shows pin 6 as idle and pin 2 as accelerate (or idle off).

All of my wiring has been done from this schematic:

http://dodgeram.org/tech/dsl/ECM/figures/ecm.gif

 

[mhenon]

OK. . for those using the Williams "Sensor kit" p/n #132034, which is the APPS sensor and wiring harness, here's the jumper I've made up. This will allow you to plug the Williams kit right into the OEM plug & wiring harness. Pretty simple. Actually timbo's jumper is much neater and will eliminate the Williams harness altogether. This is just another option.

1. 1st photo shows the OEM bellcrank with OEM APPS removed. You can see how the APPS plugs into the stock connector (my connectors been removed from the engine).

2. Jumper that allows you to connect from Williams to stock connector.

3. Williams APPS fitted to bellcrank showing the 2' harness that comes with the sensor kit, jumper and stock plug.

If this is what you need you can PM me.

Mike

 

[Gary - K7GLD]

That schematic looks different then mine. The one I have shows pin 6 as idle and pin 2 as accelerate (or idle off).

All of my wiring has been done from this schematic:

http://dodgeram.org/tech/dsl/ECM/figures/ecm.gif

WELL, that diagram LOOKS the same as mine, but has pins 2 and 6 reversed - and I could SWEAR I wired mine according to the diagram I posted just up above, and it worked perfectly. We have to go to a funeral tomorrow, and won't be able to work on the truck Saturday, so it will be Sunday before I can verify my setup - I sure don't understand the obvious difference between the 2 drawings, and why it appears we each wired ours differently, and both work!



I'm probably wrong about mine - we'll see...

 

[timbo]

That schematic looks different then mine. The one I have shows pin 6 as idle and pin 2 as accelerate (or idle off).

All of my wiring has been done from this schematic:

http://dodgeram.org/tech/dsl/ECM/figures/ecm.gif

WOW!!!!!!!! That schematic is just opposite on 2+6 from the one posted earlier!!!! That means Gary and I got ***** lucky and Bob has been BEATING his head against the wall trying to get rid of the 121 code. UNBELIEVABLE THE 2 SCHEMATICS ARE DIFFERENT!!

 

[mhenon]

... I just went out and pulled the wedge out of the duetz 6 PIN and...

How do you get that wedge out Tim. I don't need to do it but mine sounded like it "snapped" in place and I'm not sure how to un-do it!

Mike