Circuit/System Description
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Tow/haul mode enables the operator to achieve enhanced shift performance when towing or hauling a load. When tow/haul mode is selected, the tow/haul switch input signal to the body control module (BCM) is momentarily toggled to zero volts. The BCM is constantly monitoring the status of the tow/haul switch. The BCM sends the status of the tow/haul switch out on the serial data line to other control modules. The transmission control module (TCM) monitors the status of the tow/haul switch. When the tow/haul request is received, the TCM changes the shift point schedule and when TCC is applied. Cycling the tow/haul switch again disables tow/haul mode and returns the transmission to a normal shift pattern.