when replacing the ECM is there a relearn procedure to follow ? on 1997 Pontiac Grand Am

need to replace the ECM on 1997 G A

Yes, the new or manufacturer ECM you purchase for the 1997 Grand Am requires the program, or software to be "downloaded" to the hardware. So similar to you home PC, it needs the operating program loaded on it. If you purchase a used ECM. It will need to have the program loaded to match the cars V.I.N number. Their may also be theft deterrent issues to address.