For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC P071D: Trans Mode Switch B circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Trans Mode Switch B Signal | P071D | -- | -- | P071D

### Circuit/System 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 or near 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.

### Conditions for Running the DTC

• | The engine speed is greater than 500 RPM for 5 seconds.

• | Ignition voltage is between 9.0 volts and 19.0 volts.

### Conditions for Setting the DTC

The TCM detects that the Sport Mode Switch has been continuously activated for 10 minutes.

### Action Taken When the DTC Sets

• | DTC P071D is a Type C DTC.

• | The TCM freezes transmission adaptive functions.

### Conditions for Clearing the DTC

DTC P071D is a Type C DTC.

### Diagnostic Aids

• | DTC P071D detects a stuck sport pattern switch.

• | Diagnose all communication and body DTCs first.

• | Test the IPC for proper operation and lamp illumination. Refer to Diagnostic System Check - Vehicle .

• | Test the RIM for proper sport mode switch input and output operation. Refer to Control Module References .

### Reference Information

#### Schematic Reference

Automatic Transmission Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

• | Transmission General Description

• | Transmission Component and System Description

• | Electronic Component Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, engine OFF. While observing the sport mode indicator on the IPC, press the sport mode switch several times. Does the sport mode indicator illuminate On and Off with switch operation?

⇒ | Test the instrument panel cluster (IPC) for proper operation and lamp illumination. Refer to Diagnostic System Check - Vehicle .

⇒ | Test the rear integration module (RIM) for proper sport mode switch input and output operation. Refer to Control Module References .

⇒ | If the DTC resets, go to Circuit/System Testing.

2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition ON, engine OFF. While observing the sport mode indicator on the IPC, press the sport mode switch several times. Is the sport mode indicator always ON?

⇒ | Test the accessory voltage circuit for an open.

⇒ | Test the sport mode switch signal circuit for an open.

⇒ | Test the electronic PRNDL ground circuits for on open.

⇒ | Replace the electronic PRNDL assembly.

2. While observing the sport mode indicator on the IPC, disconnect the electronic PRNDL assembly from the console wiring harness connector. Is the sport mode indicator still illuminated?

⇒ | Replace the electronic PRNDL assembly.

3. Test the sport mode switch signal circuit for a short to ground. If the circuit test good replace the sport mode switch.

### Component Testing

1. Disconnect the electronic PRNDL assembly.
2. Connect a DMM, between the sport mode switch signal circuit and the ground circuit of the electronic PRNDL assembly.
3. Set the DMM to measure resistance. While observing the DMM, press the sport mode switch several times. Does the resistance toggle between very low resistance to very high resistance as the switch is pressed?

⇒ | Replace the electronic PRNDL assembly.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Manual Shift Detent Lever with Shaft Position Switch Assembly Replacement