P1761

DTC P1761

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 P1761

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

- The TCM rolling counter diagnostic is enabled.
- The Tap Up and Tap Down message health is received from the BCM.
- 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 P1761 is a Type C DTC.
- The TCM inhibits Tap Up/Down function.
- The 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
- Data Communication Schematics
- Body Control System Schematics

Connector End View Reference

- Component Connector End Views
- Inline Harness Connector End Views

Description and Operation

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. DTC P1761 is an information DTC. Troubleshoot all other panel module fault codes before DTC P1761. See Fault code (DTC) List - Car.
2. If there are no other panel module fault codes, diagnosis takes place by looking for a returning CAN-circuit fault. Go to Diagnostic tool does not communicate with high-speed GMLAN-device.
3. After performing the above steps, verify that the DTC does not return by operating the vehicle within the conditions for running fault codes (DTC). You may also operate the vehicle within the conditions you have seen from the freeze frame/failure records. If the vehicle passes the Circuit/System Verification procedure, refer to Testing for Intermittent Conditions and Poor Connections.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the Transmission Adaptive Values Learn following all transmission related repairs. Programming and Relearning