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2014 LT program car, Pull Me Over Red
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This isn't a VIN mismatch issue is it? Somehow the ECU knows it's not the same parts from before.
I am not an expert in this, but if only the engine was changed and all the electronics are the same, I would say no. The VIN or other identifier will most likely only be in the electronics.

by the way:

Welcome Aboard!:welcome:

Don't forget to introduce yourself and your Cruze here.
 

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Discussion Starter · #6 ·
I am not an expert in this, but if only the engine was changed and all the electronics are the same, I would say no. The VIN or other identifier will most likely only be in the electronics.
I'd expect the identifier to be in the ECU. The engine is just a mechanical thing with a bunch of sensors mounted on it. I don't think any of them have any VIN identifier.
 
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Hi. Sorry for lack of introduction. I currently live in New Mexico.

Bought my 2012 Cruze LS new off the lot for the exwife. Got stuck with the payment so I got the car. It has had a pretty rough life. Live on a ranch. About three months ago. Engine locked up nice and tight. Bought a replacement. Got everything swapped in and now I'm at this point.

Thanks for the pinout @anthonysmith93. To let you know there are two separate harnesses that go to the ECM. So both are needed.

Unfortunately. It appears the pinout has changed over the last few years. Were those from Alldata? I will probably need to purchase it myself for the 2012.

Thanks again everyone for the information and suggestion.
 

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Discussion Starter · #8 ·
From the samples I've seen posted here, the Alldata will tell you about any changes during the model year run. That's something my expensive Helm factory manual manual didn't have (and the Alldata is a heck of a lot cheaper).

If this engine came from a different year, or perhaps a Sonic, then the pinout might be different. There's also two different engine codes for the engine (LUW and LWE). According to gmauthority.com, "Even though they have different engine codes, the LUW and LWE are identical engines, with no perceptible differences in specifications or performance. It is unclear why they have two distinct production codes."

If there's two different codes, then I have to think there's something different that keeps them from being interchangeable on the production line. You may have just found out what the difference is.
 

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I'm really hoping you're wrong.

However with that said. The issue is still a lack of communication with the ECM itself. I would think regardless of what engine is hooked to the ECM or even if one wasn't. There would be communication with the ECM and scanner even if it was incapable of controlling the engine. I'm not 100% sure the ECM itself is good. But the car ran perfect up until the motor let go. And I have rarely seen an ECM go out.

If it does come to that point. Where can I get a new one from? I'm sure GM for $800+. I've seen them on eBay for less than $100, but I'm assuming I will need it reprogrammed by GM for a few hundred.
 

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Okay. An update. Transmission harnesses was tugged when I pulled the engine. Pulled a few of the pins from the plug. Alldata bulletin indicates the wires going to the transmission can cause a complete lack of communication with the ECM. pushed pins back in place and now I have fire. Just having issues burping the coolant system.
 

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hello! i have 2012 ls. bought it 2nd hand at a dealership. the engine went out at 60k. did anyone replace an ls with an lt engine? what would be the hurdles? would the lt engine fit the transmission and the supports? thanks!
 

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Okay. An update. Transmission harnesses was tugged when I pulled the engine. Pulled a few of the pins from the plug. Alldata bulletin indicates the wires going to the transmission can cause a complete lack of communication with the ECM. pushed pins back in place and now I have fire. Just having issues burping the coolant system.
Just more proof that if it doesn't work plug it in. I'm happy to see this was a simple fix.
 

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I just replaced the engine in my 2012 1.8 automatic Cruze. Everything went back in place like it should. I have power to the dash. But when I try to start it, I get nothing. I have tested all parts individually and all are good. When put on a scan tool I get U0100, no communication with ECM. I have checked all grounds, they appear to be good. Every thing worked fine until the engine quit.

I have read this is not the most uncommon problem when replacing the engine. But no one has given a solution.

Does anyone have an ECM pin out diagram, or know where to get one. So I can check for continuity.

Did you pull the engine out the top? Im planning to do this. Engine only.
 

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i know this is an old post , but check the main battery fuse you can jump the terminal to bypass the switch if that works , then that was your problem. the fuse breaks when you need to take the engine harness out of the car.
 
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