Detection Condition

DTC P1780 indicates TCS was not cycled during KOER self-test. Transmission Control Switch (TCS) is a momentary contact switch that allows driver to cancel overdrive gear. When TCS is pressed, a signal is sent to PCM which then uses the shift solenoids to disengage/disable overdrive gear operation. At the same time, Transmission Control Indicator Light (TCIL) is illuminated to notify driver that overdrive gear is canceled. When TCS is pressed again, overdrive gear operation is enabled and TCIL is turned off.