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 P1762: Transmission Mode Switch Signal Circuit

### Circuit/System Description

The Transmission Mode Switch Signal enables the operator to achieve enhanced shift performance when towing or hauling a load. When tow/haul mode is selected, the tow/haul switch input signal to the body control module (BCM) is momentarily toggled to zero volts. This code sets when the rolling count of the transmission control module (TCM) does not match the same value sent from the BCM.

### Conditions for Running the DTC

The engine run time is greater than 5 seconds.

### Conditions for Setting the DTC

The TCM detects an error in the rolling count value that does not match with the BCM.

### Action Taken When the DTC Sets

• | DTC P1762 is a Type C DTC.

• | The TCM forces normal shift operation.

### Conditions for Clearing the DTC

DTC P1762 is a Type C DTC.

### Reference Information

#### Schematic Reference

Automatic Transmission Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Transmission General Information

#### 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

Transmission Control Module Scan Tool Information

### Circuit/System Testing

Ignition ON, attempt to establish communication with the BCM with a scan tool.

⇒ | If no communication with the BCM, refer to Control Module References for further diagnosis.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Refer to Control Module References for TCM replacement, setup and reprogramming.