[L78toLT1]

Originally Posted by Trochoidal

I see pin 71 & 72 on X2 as unoccupied and pin 73 as ground for LT1 (2017 manual) page 11-668.

I see pin 72 on X3 as DFI High supply and pin 73 as ground for LT1 (same manual) page 11-680.

This may not be relevant to your setup, but I wanted to take a look to be a 2nd/3rd set of eyes.

Although the noid test did show no signal for pins 45-52.

You're correct on all counts, Trochoidal. I drafted the previous message, from the comfort of my couch, from memory. At my age, I should know better. Nevertheless, aside from referencing the wrong plugs/pins, the info in the preceding message is correct with regards to the harness and ground integrity. I was mistaken in an earlier message, however, when I stated that I had 4.5V on the power wires. I thought I read 4.5ish volts on my VOM, but after finally locating, and reading the diagnostic procedure in the manual, I saw where these wires should check less than 1v. I rechecked mine and they all read .45ish volts (still don't like these newfangled digital meters. I never would have made that mistake with my old analog VOM).

Noid test showed a signal on left bank pins 49 thru 52 as expected, the damn thing will run on four cylinders after all. Pins 45 - 48 have continuity, but no signal.

[JANNETTYRACING]

I will caution you to not flash the Modified tune file in to the New ECM it may Brick it.

Take a read on the new ECM and send it to me, I will make you another tune file to use.

[L78toLT1]

Originally Posted by JANNETTYRACING

I will caution you to not flash the Modified tune file in to the New ECM it may Brick it.

Take a read on the new ECM and send it to me, I will make you another tune file to use.

Thanks Ted. I believe that I understand the process, but will call and run through it with you when I get the new ECM installed, just to be sure.

[Trochoidal]

Originally Posted by L78toLT1

You're correct on all counts, Trochoidal. I drafted the previous message, from the comfort of my couch, from memory. At my age, I should know better. Nevertheless, aside from referencing the wrong plugs/pins, the info in the preceding message is correct with regards to the harness and ground integrity. I was mistaken in an earlier message, however, when I stated that I had 4.5V on the power wires. I thought I read 4.5ish volts on my VOM, but after finally locating, and reading the diagnostic procedure in the manual, I saw where these wires should check less than 1v. I rechecked mine and they all read .45ish volts (still don't like these newfangled digital meters. I never would have made that mistake with my old analog VOM).

Noid test showed a signal on left bank pins 49 thru 52 as expected, the damn thing will run on four cylinders after all. Pins 45 - 48 have continuity, but no signal.

Damn, I was hoping something would work in your favor and maybe it was a ground issue. New ECM inbound.

[Keithj3]

Did you ever get this straightened out seem to be having a similar issue.

[JANNETTYRACING]

Originally Posted by Keithj3

Did you ever get this straightened out seem to be having a similar issue.

It was a failed ECM.