conflicting advise, BCM NEW OEM need flashing or not???

**randymoe** · 07-16-2017, 04:49 AM

Replacing the BCM on my 99 TA Convertible...

Finding several sources for this part and reading posts I am seeing some say that the part needs to be flashed to the key, others say new ones do not have to be flashed to the key.

what's the scoop....

**pajeff02** · 07-16-2017, 06:47 AM

My understanding is that the key and the BCM must match. There are something like 12 different resistance values that were utilized and if they don't correspond then no start. This being said, so long as you can determine the value of the new BCM you can run the VATS bypass. Other option, if this is possible, is to have it programmed by the GM boys to match your key. Reading your key is as simple as touching the contacts with a DVOM set to read resistance in ohms.

**randymoe** · 07-17-2017, 12:05 PM

Just Received this from the GM Parts pros gmpartspros.net I think it clears it up...

Looking at the GM service manual, it says "Important: Any new body control module (BCM) will automatically program to the resistance of the key (or interrogator setting) being used at the first ignition ON cycle. This can only be done once for the life of the module."

So basically, if it is brand new, the very first time that key is used, it will program, but can only happen once.