Sport Mode Switch/Indicator Always On or Inoperative

Sport Mode Switch/Indicator Always On or Inoperative






Circuit Description

The sport and economy shift modes allow driver selection of 2 different shift patterns. Sport mode programming in the transmission control module (TCM) increases transmission line pressure and extends shift points for performance enhanced driving. In the economy mode, the TCM uses standard programming, permitting normal line pressure and shifting. The sport mode switch is a console mounted momentary contact switch located on the electronic PRNDL assembly. Accessory voltage is supplied to the electronic PRNDL assembly through the ELEC PRNDL fuse. When the sport mode switch is depressed, it momentarily contacts the switch signal circuit. The rear integration module (RIM) recognizes the voltage on the circuit and sends a class 2 serial data message to the dash integration module (DIM). The DIM sends a class 2 message to the engine control module (ECM). The ECM sends a request to the transmission control module (TCM) through the controller area network (CAN) to enable the sport mode program.


The TCM evaluates the request, and if operating conditions are correct for enabling the program, the TCM sends a confirmation message to the ECM. The ECM then requests the instrument panel cluster (IPC) to illuminate the sport mode indicator.


The sport mode feature remains enabled until the sport mode switch is pressed again. Once disabled, the TCM will return to the economy mode programming.


Diagnostic Aids

* Test the instrument panel cluster (IPC) for proper operation and lamp illumination. Refer to Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) .
* Test the rear integration module (RIM) for proper sport mode switch input and output operation. Refer to Body Control System Description and Operation (Description and Operation) .



Test Description

The numbers below refer to the step numbers on the diagnostic table.
1. Diagnose all communication and body DTCs first. The DTC may be the source of the symptom.
4. No PRNDL display could be open in the electronic PRNDL assembly accessory circuit.
6. This step tests the sport mode circuit by bypassing the electronic PRNDL assembly.