Got A 2013 Equinox that we done a new engine on would not start before did not think about it before too much thinking the old one was locked till we got it in bay. now new engine is in and cant seem to track down what the issue is. turn the key on all interior accessories appear to work but fuel gauge and temp does not do the test sweep and when key is turned to start it does not even click. after ruling out starter hooked scanner up only to find that ECM, BCM, TCM, EBCM will not scan like they are not there. I have checked the three grounding points the one behind on driver side head the main ground and the one black with white at the a/c compressor. it did not help me none that there was two weeks between tear down because wrong engine was sent. I have gone over it for 5 hrs today and cant get a grip on whats going on with it. any help is greatly appreciated. still new at the can bus systems so I am totally lost here

Start unplugging modules and see if you get coms up/

Have you check the fuse box to make sure there was no water damage. You're going to have to start doing some electrical troubleshooting.

I'm confused with the locked up engine. So was the old one locked up? Did you try to turn it before saying it was locked up?

Ok update got back on a few minutes today found I got 120 ohm'* between pin 4 and pin 14 of obd port so got a bad terminating resistor at the start of the CAN line done determined that ECM is not the culprit so its looking like BCM bad will get into it later and will update post when got it tracked down 100%

pins 6 & 14 not 4

BCM'* are a known problem.

Crazy *** can bus systems got back into it today planning on having to replace BCM but further diagnosing not only did I have 120 ohms across pins 6 and 14 but voltage check showed that can high pin 6 had 10 volts and can low pin 14 had 7 volts I was like wth is going on the entire can line was down no com with BCM ECM EBCM EPSM fo the life of me it was driving me nuts. I finally said well lets start unplugging modules. I decided to start with EPSM since I done ruled out ECM And The EPSM was second easiest to get to unplug. Well when unplugging I noticed the plug was a rare one that looked like it could be flipped the wrong way so while it was unplugged run new scan well what do you know got reading on part of them so feeling around I noticed that the clip lock on connector was turned down and on EPSM there was no tab on bottom so I flipped it over and heard it click when it plugged up run scan all modules are good and it started right up. Damn what a pita that one connector killed the entire can communication line and caused a no start. not sure who or when that was done but sure am glad its over now.

You now have 60 ohms on the system. Did a local rodent flip that connector?

I know I have 60 ohms on system now cause its working right now. lol not sure when or where that got done I never unplugged it for the engine replacement. It was What we call Customer diagnosed they said engine was bad and they had done purchased the new one wanted it replaced so we never attempted to plug a scanner up to it before hand. my boss has been doing this 34 years and he has found that some customer'* you cant tell them anything there minds get made up that'* what it is so now when they do that we just do as asked unless they want us to verify it and if it was not the issue well not our fault they wanted it done and insisted it was bad and using oil like crazy so we did it. it would not start when it came in no click nothing but until i got under it to rotate crank we just had assumed it was locked not the case it it did how ever have a dead cylinder 58 psi found after jumping off starter so it was bad but still cant figure out why the EPSM would have been unplugged before it got to us who knows its done and gone so on to the next headache.

New posts added for an unrelated issue on 2023-05-04. Moved them to a new thread for the new unrelated issue over at: https://www.gmforum.com/gmc-chevrole...issues-314652/

Please start new threads for new issues, this eliminates a lot of confusion. Please refer to https://www.gmforum.com/introduction...-first-304557/ for more details.

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