P1762

DTC P1762

Diagnostic Instructions

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

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

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P1762

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Transmission Mode Switch Signal Message Counter Incorrect

Circuit/System Description

A signal circuit is provided by the body control module (BCM) to the Tow/Haul switch. When tow/haul mode is pressed, the tow/haul switch input signal to the BCM is momentarily toggled to zero volts. The BCM is constantly sending the transmission control module (TCM) serial data messages with information regarding the status of the Tow/Haul switch. This signals the transmission control module (TCM) to change the shift points, the application of TCC, and transmission line pressure. The TCM sets this DTC when it detects a discrepancy in the structure of this message causing its integrity to be questioned.

Conditions for Running the DTC

* The TCM rolling counter diagnostic is enabled.

* The Tow/Haul message health is received from the BCM.

* The ignition voltage is 8.6 volts or greater.

* The engine speed is 400 RPM or greater for 5 seconds.

Conditions for Setting the DTC

The TCM detects an error in the rolling count value that does not match with the BCM count, 3 times within 10 seconds.

Action Taken When the DTC Sets

DTC P1762 is a type C DTC.

Conditions for Clearing the DTC

DTC P1762 is a type C DTC.

Diagnostic Aids

If the electrical circuit tests are OK and the shift pattern is not occurring, there may be a mechanical/hydraulic condition that prevents operation. Refer to Symptoms - Automatic Transmission Symptoms - Automatic Transmission.

Reference Information

Schematic Reference

* Automatic Transmission Controls Schematics Electrical Diagrams

* Data Communication Schematics Electrical Diagrams

* Body Control System Schematics [1][2]Body Control Systems

Connector End View Reference

* Component Connector End Views A/C Compressor Clutch

* Inline Harness Connector End Views X100

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Description and Operation

Electronic Component Description Electronic Component Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Programming and Relearning for scan tool information

Circuit/System Verification

1. DTC P1762 is an informational DTC. Diagnose all other body control module DTCs prior to DTC P1762. Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. If there are no other body control DTCs, diagnosis is accomplished by looking for an intermittent CAN circuit fault. Refer to Scan Tool Does Not Communicate with High Speed GMLAN Device Scan Tool Does Not Communicate with High Speed GMLAN Device.

3. 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.

Repair Instructions

* Perform the Reset Transmission Adapts Reset Transmission Adapts following all transmission related repairs.

* Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.