LLY ECM and TCM pinouts

thunder550

Active member
Apr 2, 2013
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Anyone have diagrams of the ECM and TCM pinouts for a 2005 LLY? I am trying to diagnose a couple of codes...wanting to check continuity from the VSS and the accelerator pedal to the ECM and/or TCM.
 

clrussell

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Sep 23, 2013
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Thunder I can get them for you in a little while if no one else has.


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clrussell

pro-procrastinator
Sep 23, 2013
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rcashman

New member
Jun 7, 2023
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Idaho
54602255ff26bff351254f3aefbb664d.jpg

4645f169a212b01460e812c7d673997f.jpg

8f372817544fe0c6ad55bd290c917642.jpg

05c64b9b1f8d5a81a365f126b4b12c8c.jpg



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Question. In the red tcm connector pin 31. Back probing I'm only getting 11.64 volts with KOEO. Bat voltage is 12.18 in the clr connector pin 3. Do you know if the "12 Volt reference" on pin 31 in the red connector has to be at or above 12 volt KOEO or is that 12 volt KOER?
 

Ron Nielson

Active member
Oct 11, 2009
779
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Berryton, KS
References voltages (like the 5V reference supplied to 3 wire sensors) are supposed to be regulated to almost that exact voltage by the ECM. I would check with the engine running and see what voltage you get vs just key on. A battery voltage of 12.18 is a low battery, about 50-60% charged. Put it on the charger.
 

rcashman

New member
Jun 7, 2023
19
1
3
Idaho
References voltages (like the 5V reference supplied to 3 wire sensors) are supposed to be regulated to almost that exact voltage by the ECM. I would check with the engine running and see what voltage you get vs just key on. A battery voltage of 12.18 is a low battery, about 50-60% charged. Put it on the charger.
Yeah i put the charge on it. I thought it should be closer to 12v Got a serial 2 com issue. Still tracing.
Narrowed it down to the entire trk :)
What a headache. :ROFLMAO:
Good thing im strong willed or thick headed. Haven't put a label on it yet.
 

Ron Nielson

Active member
Oct 11, 2009
779
149
43
Berryton, KS
enter this in your browser as a URL:
gm upfitter 2003 electrical manual full size

The older truck listings are all mixed up and very hard to find what you want.
 
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