Transmission Control Switch (TCS)

The transmission control switch (TCS):

• Seats in the end of the gearshift lever.
  • A cover retains the TCS to the gearshift lever.
• Is a momentary contact switch.
• Commands the powertrain control module (PCM) to disengage or engage the overdrive function of the transmission.
  • When overdrive (D) is disengaged, the message O/D OFF will illuminate on the instrument panel.