P1761
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
- Tap Up Tap Down Shift Switch Signal Message Counter
Circuit/System Description
A 12 volt signal circuit is provided by the body control module (BCM) to the plus or minus buttons. When a plus or minus button is pressed, a corresponding voltage drop occurs across the resistor network embedded in the switches. 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
* The TCM rolling counter diagnostic is enabled.
* The Tap Up and Tap Down health 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 at least 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, within 10 seconds.
Action Taken When the DTC Sets
* DTC P1761 is a Type C DTC.
* The TCM disables TAP Shift operation.
Conditions for Clearing the DTC
DTC P1761 is a Type C DTC.
Reference Information
Schematic Reference
* Automatic Transmission Controls Schematics ([1][2]Electrical Diagrams)
* Data Communication Schematics ([1][2]Electrical Diagrams)
* Body Control System Schematics (Electrical Diagrams)
Connector End View Reference
* Component Connector End Views (Connector End Views By Name)
* Inline Harness Connector End Views (Connector End Views By Number)
Description and Operation
* Transmission General Description (Transmission General Description)
* Transmission Component and System Description (Transmission Component and System Description)
* Electronic Component Description (Electronic Component Description)
* Body Control System Description and Operation (Description and Operation)
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 P1761 is an informational DTC. Diagnose all other body control module DTCs prior to DTC P1761. 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. After performing the above steps, then 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. If the vehicle passes the Circuit/System Verification procedure then, refer to Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections).
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.
Perform the Service Fast Learn Adapts (Programming and Relearning) following all transmission related repairs.