03 tahoe, security system

hey guys i have a 2003 chevy tahoe this really doesnt pertain to this forum but im hoping someone can help i did an engine swap batterry was disconnected for a bout a week but the securty system is locking me out i tried leaving the key on for a half hour and nothing i dont get any injector pulse can anybody pls help me is their some type of cycle without having to go to the dealer for a tech 2

I tried to search for you but couldn't find it. During your engine swap, did you also replace the BCM, or ignition lock switch? When you try to start, is the padlock symbol on the dash flashing, or does it come on for a few seconds and then go out? If the symbol is flashing, the following procedure is for reprogramming, after you've replaced part of the PASSLock II system: --If you're in a garage, either be sure to to switch off the autolamps, or connect a battery charger. 1. Attempt to start engine, leaving key on the "run" position. The padlock symbol on the dash will be flashing. 2. After 10 minutes, the padlock should turn off. Turn ignition off. 3. Repeat 1 and 2, two more times. (Three 10 minutes cycles in total.) 4. After all this, if all is well, the engine should start on the next try.

thanks for the reply i did not replace the bcm or mess with the ignition swith so hopefully that will work