Does the GT Tuner “lock” the PCM after flashing it?
PCM “locking” is a feature that became available with the Gen III LS1/Vortec PCM. PCMs have a “password” that is required to access them, and there is a specific algorithm for establishing the “password” from information provided by the PCM. It is possible, however, to change this “password” to something else. Some custom PCM tuners will change the “password” for the stated reason of preventing others from accessing the tune stored in the PCM. There are a few problems with doing this, the biggest being that once the password is changed, only the person who changed it will be able to program the PCM again. The customer will be “stuck” going back to the same PCM tuner if they make any further modifications, and if they wish to go to another PCM tuner, they will need to purchase a new PCM which is not locked. Some PCM tuning customers may be OK with this, but at Trifecta Performance, we do not believe this is our decision to make for the customer. We also acknowledge that changing the PCM
