I'm looking to buy New ECM for my 09 SS. So, do I need reprogram or just install right away in my car? Appreciate any help.

 

I'm pretty sure the new ECM will need to be paired with your HHR by using a Tech II scan tool, that's really a "dealer only" deal.

The various modules in HHR's are keyed to the VIN, without being matched up to your HHR, the new ECM won't talk to the other modules.

 

X2. The vin,options and the milage have to be programed to the new ECM.

 

There was a guy on eBay selling used ECMs programed to your VIN. The one I had was good. You still need to have the crankshaft position sensor re-learned, that requires at least a good shop that has the right computer (not necessarily a TechII).