Quote:Do not swap control modules. It's a word of caution that bears repeating as more new GM models are introduced with the Global Architecture electrical system.


These models now include:
•2012 Sonic and Verano (and, in Canada, Orlando)
•2011-2012 Cruze and Volt
•2010-2012 LaCrosse, Regal, SRX, Camaro, Equinox and Terrain


The Global Architecture electrical system does not allow control modules to be swapped between vehicles. Swapping control modules will result in a no start condition on both vehicles and will damage both modules due to the new vehicle security code protocol (environment).


Do not swap the following control modules:
•Engine Control Module (ECM)
•Radio
•Body Control Module (BCM)
•Electronic Brake Control Module (EBCM)
•Sensing and Diagnostic Module (SDM)
•Transmission Control Module (TCM)
•Electronic Climate Control (HVAC)
•Electric Power Steering
•Hybrid Powertrain Control Module
•Vehicle Communication Interface Module
•Instrument Panel Cluster

Quote:Global A vehicles use a vehicle specific environment identifier to prevent module swapping. Not all modules use the identifier. The IPC, EBCM, HVAC, SDM, and ECM usually always do. Each of these modules will have learned the digital identifier during initial configuration.

In operation, the BCM is the controller of the environment identifier. It sends the identifier over serial data as a challenge. The modules respond by comparing the internally stored ID against the ID sent by the BCM. If they match, the modules send the ID back to the BCM over the data line. Depending on programming, the BCM may have to see one or several incorrect responses from the modules to take action. At this point, the BCM will disable starting and the modules will set B3902 for incorrect identifier received.

When the modules receive a correct identifier after the problem is rectified, they are supposed to clear the B3902 and restore normal operation. In the real world, this doesn't always happen. The modules may lock on the incorrect ID and become permanently inoperable.