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

-
Up and Down Shift Switch Signal Circuit

Circuit/System Description

The driver shift request (DSR), also known as the TAP Up/Downshift manual shift function, allows the driver to select the desired range of gears for current driving conditions. The DSR shift system is activated when the gear selector is in the manual position. The DSR system is deactivated in all other range positions. When DSR is selected, a signal is sent to the body control module (BCM) and the also to the transmission control module (TCM). Each time a signal is sent, an internal counter in the BCM and TCM increments. Both counters must have the same value. This code sets when the rolling count value of the TCM does not match the same rolling count value sent from the BCM.

Conditions for Running the DTC

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.

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 6L45/6L50/6L80/6L90 - Automatic Transmission

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

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 Control Module References for scan tool information

Circuit/System Verification

Note:
If other DTCs are set, diagnose those DTCs first.

1. Ignition ON, verify with a scan tool the Tap Up/Down Switch parameter displays ON in the Chassis Data list under BCM.

• If the parameter value is incorrect

Refer to Circuit/System Testing below.

• If the parameter value is correct

2. Ignition ON, verify with a scan tool the Tap Up/Down parameter displays UP when pressing the plus (+) switch and Down when pressing the minus (-) switch.

• If the parameter value is incorrect

Refer to Circuit/System Testing below.

• If the parameter value is correct

3. Ignition ON, verify with a scan tool the Driver Shift Control parameter in the Transmission Data list changes from, Inactive to Active when placing the automatic transmission shift lever in manual mode position.

• If the parameter value is incorrect

Refer to Circuit/System Testing below.

• If the parameter value is correct

4. Ignition ON, verify with a scan tool the Driver Shift Request Switch 1 displays NONE in the transmission data list.

• If the parameter value is incorrect

Refer to Circuit/System Testing below.

• If the parameter value is correct

5. Ignition ON, verify with a scan tool the Driver Shift Request Switch 1 displays Upshift when pressing the plus (+) switch and Downshift when pressing the minus (-) switch.

• If the parameter value is incorrect

Refer to Circuit/System Testing below.

• If the parameter value is correct

6. 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 you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.

Circuit/System Testing

If no other DTCs are set, diagnosis is accomplished by testing for a condition on the CAN circuit. Refer to Scan Tool Does Not Communicate with High Speed GMLAN Device Scan Tool Does Not Communicate with High Speed GMLAN Device.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

Control Module References Control Module References for control solenoid valve assembly replacement, programming, and setup.