APP not working on 5.3L swap

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Dec 29, 2015 | 04:06 PM

Tom2T

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From: Independence, OR

APP not working on 5.3L swap

Looking for some help on my swap.

This is an 05 LM7/4l60E with all original parts with exception of the PCM. Harness rework was per LT!SWAP.com, and the PCM was purchased and programmed by him for standalone operation.

Completed the first start and runs good, but no change in RPM with operation of the APP.

Checked the following:

Throttle body wiring pinout and continuity.

MAF wiring and continuity.

TAC wiring and continuity.

APP wiring and continuity.

OBD2 port wiring.

Confirmed grounds.

Did not have the check engine light wired on start and have not been able to confirm OBD2 feed to the scantool mx I'm using. Going to install a check engine light and work on pulling codes/diagnostics with the scan tool.

Any suggestions on additional checks would be appreciated. I want to validate harness operation so I can continue with accessory installation without concern with the basic harness.

Current setup for testing.

Thanks for the help
Tom

Dec 31, 2015 | 02:15 PM

G-Body

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From: Downers Grove, IL

Sounds like there might be a couple issues going on.

Your scan tool should be able to connect with the key in the run position. You do not need to have the engine running to hook into the OBD 2 port, just need everything powered up. I would start by looking into this as it may solve your other problems. My first guess would be missing power, Blue PCM connector pins 19, 20, 57, and 75 should all have power with the key on.

What PCM do you have and does it match your TAC and pedal?

Your pedal should work the throttle body with the key on and the engine off. Once you can connect the scan tool you should be able to use it to see the change in the APP sensor.

Jan 1, 2016 | 08:59 AM

aknovaman

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From: Hog Back, KS

If its drive by wire, I bet the pcm file is messed up. Where in OR are you located? Near Portland? I have a buddy there that can fix it.

Jan 1, 2016 | 10:46 AM

ls1nova71

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From: Liberty, MO

Does the throttle body make any noise at all when the key is turned to the run position? It should just make a quick click noise. If it doesnt, you could possibly be missing the power wire on the TAC itself, seen that a couple of times.

Jan 1, 2016 | 12:17 PM

Tom2T

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From: Independence, OR

It works

G-body
Thanks so much for the pointers.

Double checked the power wires and they checked good. Got the Scantool hooked up and running with power on, cleared the codes and heard the throttle body cycle. Saw the TPS reading change and tested the pedal which worked!

Next I did a test fire and all is good!

I did add power to the PND switch but don't know if that would have been an issue??

Anyway on to building accessory hook-ups and mounting the cab to fit PCM, etc.

Thanks again
Tom

Jan 1, 2016 | 12:24 PM

Tom2T

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From: Independence, OR

aknovaman
I'm 45 miles south of Portland, it would be great to meet your buddy sometime. I had a base setup programmed in the PCM, but will need some changes when I get closer to the end of the project. Message me if you like and we'll go from there.

ls1nova71
Yes I caught that in one of your earlier posts. Main problem was a guy on the steep side of the learning curve...