All 2009 HHRs are flexfuel and VVT don't know about others.
YMM is probably some special sales code, like a package installed for a special offer by GM.

 

In which case you take it to local garage and ask them to relearn the sensor, the one from the donor car might work.[/QUOTE]
I followed the link you provided, very interesting!
I do have a Bluetooth diagnostic plug model LSB2 from www.bluedriver.com for my other car which is a 2012 Mini Cooper S, but the capabilities are very limited. I intend to spend some money to get a real scanner for my HHR. A scanner which would allow me to perform the procedure outlined in the link you posted. Which model would you, or in general, this community recommend and is worth buying?

 

Foxwell NT 650

https://www.foxwelldiag.com/products...ll-nt650-elite

 

this explains things

 

P0315 is for when a new WCM is installed with NO variation in memory. Changing the sensor will not throw a code but, will affect long term efficiency. You might not notice the difference. Re learning is one of those things that should be done but the engine will function without.
Each sensor has its own variation by a tiny bit.

 

donbrew, you mean ECM not WCM, right?

 

What this community so far accomplished in the matter, option NU5 versus option NU1:
The question was whether a 2.2L engine with the option NU5 could be replaced with an engine with the option NU1.
An engine with the option NU5 is a flex-fuel capable engine out of a 2009 HHR; the engine with the option NU1 is an engine out of a Cobalt from the same year.
Both engines have the number 5 as the 8th digit of the VIN.
Both engines have the LAP option: ENGINE GAS, 4 CYL, 2.2L, MFI, VVT, ALUM, DOHC. I guess VVT stands for Variable Valve Timing.
In 2008, we had the savings and loans crisis caused by mortgaged backed securities and the mortgages were junk and a lot of them defaulted which shook the financial institution and sent some car manufacturers into crisis (one reason why there were only 216 HHR SS PANEL versions produced. Flex-Fuel was just a Hype of the time and it is possible that other then more resistant materials in the fuel delivery system there are no other differences between the two options, option NU1 and NU5; but we (I) do not know for sure yet.
What I gather however is that the ECM needs to go through a re-programming or re-learning process as noted by donbrew, and the process to do so was provided by Oldblue by posting this link:
https://www.totalcardiagnostics.com/...-scannerreader
To perform the re-learning procedure, Oldblue recommends the Foxwell NT650 scanner.
I feel quite confident now that the engine I bought with the NU1 option will do its job once in my HHR; thank you all for your expertise.
I will document the progress here and let the community know how the project goes along.

 

Your comments invite much discussion but I'll stick to what's relevant to the task at hand.

Actually, the only question in the OP was:

"Will the wire harness be the same?"

The best answers are, "No." and "Which one?"

Hope you found all the other information useful. From your last comments It's clear you don't quite understand all the differences in the flex fuel version. Neither do I. But maybe what little I think I know that might be useful to you.

I know of no difference in the two motors other than periferal hardware which is easily swapped, and the fuel injectors and seals, also easily swapped. Possibly some other seals that might come into contact with fuel, IDK.

A major distinguishing features of the FlexFuel version is a completely different program in the ECM, including potentially more aggressive VVT and ignition timing, and a routine for calculation ethanol %. Most of the other differences as far as I know involve compatability with the very corrosive properties of E85. This includes at least one difference in the BCM, I believe.

It would definitely have been better if they had sold you an actual HHR engine, but at this point it seems that the safest course is to simply swap in the HHR-specific stuff, and leave the computers alone. Do this and you should be able to use your HHR harness(es.) Trying to (unnecessarily) convert the car into a Cobalt-style non-FlexFuel car by messing with control modules risks unintended consequences.

There are pros and cons to E85 (mostly pros, in my opinion,) and there are pros and cons to a FlexFuel motor (mostly pros, in my opinion,) even if E85 is never used, (and E85 isn't even available in much of, if not most of, the country.

But, your car, your decisions.

BTW, NU1 & NU5 are just diffent levels of California emission .. something. (I was going to say certification, but that might be yet another RPO.) To unnecessarily restate what should be clear by now, LAP & LE8 are just RPO's for slightly different versions of very similar engines. All 2009 2.2 HHR's had RPO LE8. All 2009 2.2 Cobalts had RPO LAP.

Good luck!

PS - Some day I'd like to know WTF Chevy decided to go all-FlexFuel in HHR, and no FlexFuel in Cobalt, No option. Weird, huh?

 

Actually the wire hardware the same as is the sensors , just the ECM is programmed differently. So, if you do the swap, just don’t use E85 .

 

Why not? The car already has everything it needs for E85 and he pretty much needs to use his old larger & E85 compatible injectors because that's what his ECM is programed for and the LAP injector will be trouble unless he gets a 2009 Cobalt 2 2 ECM, and who know what complications that would bring.

If he doesn't like E85, fine, just don't use it, of course.