Circuit/System Description

When the shift lever is placed in the M position, the transmission will enter manual mode, also known as tap shift. The manual mode allows the vehicle operator to select an upshift by pressing the plus (+) button or downshift by pressing the minus (-) button. The body control module (BCM) supplies a signal circuit to the shift controller. The shift controller has switches connected to a resistor array. A voltage drop occurs across the resistor network. When the plus or minus button is pushed, a corresponding voltage drop occurs across the resistor network. This voltage drop is monitored by the BCM. The BCM will send the request to the transmission control module (TCM) for an upshift or downshift.