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 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.

The Sport Mode switch remains closed, low voltage, for 600 seconds.

DTC P071D is a Type C DTC.

DTC P071D is a Type C DTC.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transmission General Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Transmission Control Module Scan Tool Information

Special Tools

J 35616 GM-Approved Terminal Test Kit

Turn ON the ignition, with the engine OFF. Cycle the tow/haul switch while observing the Tow/Haul Mode parameter on the scan tool.

1. Remove connector from the tow/haul switch. Using the J 35616 GM-approved terminal test kit, install a fused jumper wire from the tow/haul switch signal and ground circuits of the tow/haul switch connector.

⇒	If the scan tool Tow/Haul Mode indicates a status change, replace the switch.

2. Using the DMM and the J 35616 , measure the voltage at the tow/haul switch signal circuit of the tow/haul switch connector.

⇒	If Ignition Voltage is measured, test the ground circuit of the tow/haul switch for an open or shorted condition.

3. Using the DMM and the J 35616 , measure the voltage at the tow/haul switch signal circuit of the body control module (BCM).

⇒	If Ignition Voltage is measured, test the signal circuit of the tow/haul switch for an open or shorted condition.

⇒	If Ignition Voltage is not measured, replace the BCM.

Verify the Tow/Haul Mode parameter on scan tool while cycling the tow/haul switch.

Perform the Diagnostic Repair Verification after completing the repair.