GMC Envoy transfer case control module issue causing 4WD light activation and shifting problems after battery replacement on GMC Envoy

Some GMC Envoy owners report experiencing issues with the transfer case control module following a battery replacement, such as the activation of the 4WD light and shifting problems. These issues may arise if the Transfer Case Control Module (TCCM) did not receive a wake-up call during key-up, resulting in the service 4WD light being illuminated. Additionally, some owners suspect that engineers at GM may have overlooked the TCCM's memory retention setup, leading to confusion and malfunction. Reprogramming the TCCM with the latest software calibration can potentially resolve these issues and restore proper 4WD system functionality. Furthermore, faulty components like the transfer case encoder motor position sensor or selector switch may also trigger the service 4WD message. In some instances, a logic lock-up within the TCCM may occur, necessitating temporary fixes such as removing the 4WD fuse or resetting the TCCM, though further diagnosis may be required for a permanent solution. Addressing these potential causes systematically is crucial for resolving the transfer case control module issues in the GMC Envoy.