I just installed a brand new PCM on my Buick enclave 2008 gives me the P0602 code, the vehicle does not work, and some tell me it takes flasher PCM? I would like to know how flacher PCM (the stage) and is what a poor fitting of the box can cause this code "programming error."
P0602 simply means the control module is not programmed.
Programming is generally required when installing a new PCM in most modern vehicles.
You will need to take the vehicle and the new PCM to a shop with the specialize equipment to program the computer.
There really isn't a DIY solution to this problem.