6T70/6T75 - Automatic Transmission

DTC P1761

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 Descriptor

DTC P1761

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Up and Down Shift Switch Signal Message Counter

Circuit/System Description

A signal circuit is provided by the body control module (BCM) to the resistor network embedded in the plus or minus buttons. When a plus or minus button is pressed, a corresponding voltage drop occurs across the resistor network. This voltage drop is monitored by the BCM. The BCM will send the request to the transmission control module (TCM) to perform the upshift or downshift. The TCM is constantly monitoring the serial data sent from the BCM for the correct number and sequence of counts for Tap Up and Tap Down function.

Conditions for Running the DTC

* Tap Up and Tap Down message health is received from the BCM.

* Engine speed is 400 RPM or greater for 5 seconds.

Conditions for Setting the DTC

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 P1761 is a Type C DTC.

* TCM inhibits Tap Up/Down function.

* TCM inhibits manual shifting of forward gears.

Conditions for Clearing the DTC

DTC P1761 is a Type C DTC.

Reference Information

Schematic Reference

* Automatic Transmission Controls Schematics 6T70/6T75 - Automatic Transmission

* Data Communication Schematics Electrical Diagrams

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

Connector End View Reference

* Component Connector End Views Sunshade - Left Front

* Inline Harness Connector End Views X110

Description and Operation

Electronic Component Description Electronic Component Description

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

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 P1761 is an informational DTC. Diagnose all other body control module DTCs prior to DTC P1761.

• If other body control module DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle

• If no other body control module DTCs are set

2. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.

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.