Transmission Control Switch (TCS) And Transmission Control Indicator Lamp (TCIL)

The transmission control switch (TCS) is a momentary contact switch. When the switch is pressed, a signal is sent to the PCM to allow automatic shifts from 1st through 4th gears or 1st through 3rd gears only. The PCM energizes the transmission control indicator lamp (TCIL) when the switch is OFF. The TCIL indicates overdrive cancel mode activated (lamp ON). When the TCIL is flashing, it indicates electronic pressure control (EPC) circuit shorted or a monitored sensor failure.