Transfer Case Shift Control Module (TCCM)
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The TCCM is new for 2003. The TCCM has been standardized for all K trucks. The TCCM contains the same hardware, boot software, and operational software found in other GM K trucks. The only difference is the calibration file downloaded into the TCCM memory. The TCCM comes with the appropriate calibrations out of the factory, but new calibrations must be flashed into the TCCM during service. This is especially important if a new TCCM is installed during service. Calibration files may be introduced irregularly. See your technical service bulletins. Refer to Transfer Case Control Module Reprogramming .