Red3quarter

Ok, my truck has been doing the Unlock and lockup of the TC every now and then. so tonight i cleaned the grounds on the truck and reset the APPS. I also had found a few threads that linked me to a procedure on ATS's website on how to jumper the APPS to the PCM and skip over the ecm. I did that and it didn't work one bit...it gave me a very laggy kinda unresponsive peddle. its wasn't a dead peddle though. It threw a check engine light, it disconected my betteries again and undid what this procedure said to do and hooked the original wires back up and now the truck run fine again and is actually all more responve than it originally was before i cleaned up my grounds and reset the APPS. I know i followed the prcedure from the ATS site perfect, and i always triple check myself when i work on anything just for insurance.I have no idea what went wrong and if having spliced into the wire i did will hurt anything in the future? Anyone else that has used this, did it work? I'll probably just spend the $40 and get the DTT noise filter. Any replies are appriciated.
matt


Here's the link to what i did:
http://www.atsdiesel.com/PDF/APPS%20...20Fix%20A1.PDF

Red3quarter

bumping this back up

Mike D

Send AlpineRam a PM. If I remember correctly he did something like this to his truck.

Silverjay

I didn't have to go to the DTT noise filter to fix mine, but that was my next stop. Don't try a HAPPI box. It made no difference on mine.

AlpineRAM

I did re-route the cable from the ECM to the PCM and used a shielded cable with the shield connected to the ground. Since the resistance between the APPS in to the PCM and the TPS out from the ECM to the PCM is 28 kiloohms it is reasonable to assume that the signal for the TPS signal to the PCM is generated by the ECM and not simply the APPS output voltage.
As a failsafe the PCM can talk to the ECM over the can-bus and give it some info on how much load is on the engine even if the APPS fails completely in supplying the info to the ECM.
The ATS instructions won't do any good if the noise is caused by interference from magnetic fields since the old wire stays connected like na antenna to pick up the noise. I replaced (read cut both ends of the original cable) the stock ECM pin 28 cable (orange/dark blue) to pin 23 on the C1 on the PCM with the shielded cable (I used Cat5 , used all the pairs for the connection and soldered the shield mesh to get a good point to ground it.
This solved my hunting problem.

HTH
AlpineRAM

Disclaimer- it helped me, won't necessarily do anything good for you. Get a service manual for your truck and check the wiring colours and the connector pinouts for your model

Red3quarter

Thank you for the information AlpineRam, it makes sense and i'm going to wait and do all that till i get my hands on the service manual.
matt