Transmission Mode Switch: Testing and Inspection

Transmission Control Switch (TCS)/Transmission Control Indicator Lamp (TCIL)-SHO only













The transmission control switch (TCS) is a momentary contact switch. When this switch is pressed, a signal is sent to the powertrain control module (PCM). The powertrain control module (PCM) then energizes the transmission control indicator lamp (TCIL) and toggles Solenoid 3 (SS3), applying the forward clutch to provide engine braking and canceling fourth gear operation.

Note: TCIL will also flash if the EPC circuit is shorted.

Sensor:
Transmission Control Switch (TCS)

Transmission Function:
Disable fourth gear operation

Symptoms:
No overdrive cancel when switch is cycled.

DTC:
632 (three digit), tested during Key On Engine Off (KOEO) On-Board Diagnostic only. Refer to Three (3) Digit Codes

Actuator:
Transmission Control Indicator Lamp (TCIL)

Transmission Function
Indicates overdrive cancel mode activated (lamp on) and EPC circuit shorted (lamp flashing)

Symptoms:
Failed "ON"-Overdrive cancel mode always indicated, no flashing for EPC circuit shorted. Failed "OFF"-Overdrive cancel mode never indicated, no flashing for EPC circuit shorted.

DTC:
631 (three digit). Refer to Three (3) Digit Codes