Transmission Control Switch (TCS)

DESCRIPTION
The Transmission Control Switch (TCS) is a momentary control switch. When the switch is pressed, a signal is sent to the Powertrain Control Module (PCM) to allow automatic shifts from first through fourth gears or first through third 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) and Electronic Pressure Control (EPC) circuit shorted (lamp flashing) or monitored sensor failure.

NOTE: TCIL will also flash if the EPC circuit is shorted, or monitor sensor or actuator fails.

SENSOR
Transmission control switch.

SYMPTOMS
No overdrive cancel when switch is cycled.

DTC
P1780

ACTUATOR
Transmission Control Indicator Lamp (TCIL).

SYMPTOMS:
- Failed ON - overdrive cancel mode always indicated, no flashing for EPC circuit shorted, or monitored sensor failure.
- Failed OFF - overdrive cancel mode never indicated, no flashing for EPC circuit shorted, or monitored sensor failure.