K 1500 Suburban 4WD V8-5.3L VIN Z Flex Fuel (2003)
Tow/Haul Switch: Description and Operation
4L60-E/4L65-E
4L60-E/4L65-E
Tow/Haul Mode Switch
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. This signals the powertrain control module (PCM)
to extend the length of time between upshifts and increase transmission line pressure. Cycling the tow/haul switch again disables tow/haul mode and
returns the transmission to a normal shift pattern.
