6L80-E Automatic Transmission

DTC P0751

DTC Descriptor
This diagnostic procedure supports the following DTC:

DTC P0751 Shift Solenoid (SS) 1 Valve Performance - Stuck Off

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description
The shift solenoid (SS) valve 1 is part of the lower control valve body. The SS valve 1 is a normally closed (NC) solenoid valve and controls fluid to the clutch select valve 3- and related clutches. During this diagnostic test, intrusive actions are taken by the transmission control module (TCM) to test the SS Valve 1 to see if the valve is stuck OFF. When in first gear engine braking, if first gear ratio is not achieved in a predetermined period of time and the closest gear ratio detected if fourth, the TCM commands second gear and if second gear ratio is attained this indicates a stuck OFF SS Valve 1 and the DTC will set.

Conditions for Running the DTC
^ First gear locked is commanded.
^ Commanded gear slip is equal to or less than 75 RPM for 2 seconds.

Conditions for Setting the DTC
The TCM detects second gear ratio is achieved.

Action Taken When the DTC Sets
DTC P0751 is a Type A DTC.

Conditions for Clearing the DTC
DTC P0751 is a Type A DTC.

Diagnostic Aids
When attempting to set transmission performance DTCs, it may be helpful to observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.

Reference Information

Schematic Reference

Connector End View Reference
^ Automatic Transmission Inline 16-Way Connector End View
^ Automatic Transmission Internal Connector End Views

DTC Type Reference
^ Diagnostic Trouble Code (DTC) Type Definitions
^ Diagnostic Trouble Code (DTC) List/Type

Electrical Information Reference
^ Circuit Testing
^ Connector Repairs
^ Testing for Intermittent Conditions and Poor Connections
^ Wiring Repairs

^ Special Tools Required
- DT 47825-1?

Circuit/System Verification
1. Perform the transmission fluid checking procedure. Refer to Transmission Fluid Checking Procedure. Procedures
2. Operate the vehicle in drive from a complete stop, with the calculated throttle position greater than 15% to obtain 56 km/h (35 mph) 2 times. If the DTC resets, go to Circuit/System Testing.

Circuit/System Testing
1. Perform the line pressure check procedure. Refer to Line Pressure Check Procedure. If the pressure is out of specification correct that concern first.
2. Perform the control solenoid (w/body and TCM) valve assembly cleaning procedure and retest the DTC as outlined in the Circuit/System Verification steps. Refer to Control Solenoid Valve and Transmission Control Module Assembly Cleaning. Control Solenoid Valve & TCM Assembly Cleaning If the DTC resets, continue on with testing.
3. Perform the control solenoid (w/body and TCM) valve assembly inspection procedure. If a concern is found, repair or replace the control solenoid (w/body and TCM) valve assembly.
4. Perform the control solenoid (w/body and TCM) valve assembly solenoid performance test procedure. Refer to Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test. Control Solenoid Valve & TCM Assembly Solenoid Performance Test If the shift solenoid 1 is found to be leaking or stuck OFF, replace the control solenoid (w/body and TCM) valve assembly.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Replace the control solenoid (w/body and TCM) valve assembly. Refer to Control Module References for replacement, setup, or programming. Programming and Relearning