Sport Mode Indicator Lamp/Switch Diagnosis

Circuit Description
With the engine running and the transmission in Drive 4, the Sport Mode Indicator Lamp should transition from On to Off or from Off to On with each press of the Sport Mode Selector Switch. The ignition voltage is supplied directly to the indicator bulb. The Transmission Control Module (TCM) controls the lamp by grounding the control circuit via an internal solid state device called a driver. The Sport Mode Selector Switch signal circuit is pulled up to B+ within the TCM. The other side of the switch connects to ground. When the switch is on, the signal voltage is pulled low. The TCM interprets this as sport mode requested. The Sport Mode selection causes the TCM to use a more aggressive shift schedule for improving performance and providing a more positive shift feel.

Vehicles equipped with Fuel Cap Lamps utilize the Sport Mode lamp to indicate a transmission malfunction. In these vehicles, the Sport Mode Lamp flashes at 200 millisecond intervals when the TCM commands the lamp ON.

Vehicles not equipped with Fuel Cap Lamps are equipped with a dedicated Service Transmission Lamp (STL) on the Instrument Panel Cluster (IPC). The STL illuminates steadily when the TCM commands the lamp ON.

Diagnostic Aids
An intermittent may be caused by the following:
^ Corrosion
^ Rubbed through wire insulation
^ Broken wire inside the insulation

Refer to Symptoms for intermittents. Symptom Related Diagnostic Procedures

Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
7. If the other indicator lamps in the instrument cluster are functioning, the feed circuit is OK.