6L50/6L80/6L90 - Automatic Transmission
DTC P0751
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 P0751
- Shift Solenoid (SS) 1 Valve Performance - Stuck Off
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, 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
Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference
* Electrical Center Identification Views
* Component Connector End Views
* Splice Pack Connector End Views
* Inline Harness Connector End Views
Electrical Information Reference
* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs
Scan Tool Reference
* Scan Tool Output Controls (Scan Tool Output Controls)
* Scan Tool Data List (Scan Tool Data List)
* Scan Tool Data Definitions (Scan Tool Data Definitions)
DTC Type Reference
* Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
* Diagnostic Trouble Code (DTC) List/Type (Diagnostic Trouble Code Descriptions)
Special Tools Required
DT-47825 Control Solenoid Test Plate
Circuit/System Verification
1. Perform the Transmission Fluid Check (Transmission Fluid Check) .
2. Operate the vehicle in drive from a complete stop, with the calculated throttle position greater than 15 percent 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 (Line Pressure Check) .
• If the pressure is out of specification correct that concern first.
2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Cleaning (Control Solenoid Valve and Transmission Control Module Assembly Cleaning) and retest the DTC as outlined in the Circuit/System Verification steps.
• If the DTC resets, continue on with testing.
3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and Transmission Control Module Assembly Inspection) .
• If a concern is found, repair or replace the control solenoid (w/body and TCM) valve assembly.
4. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test (Control Solenoid Valve and Transmission Control Module 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
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
* Replace the control solenoid (w/body and TCM) valve assembly. Refer to Control Module References for replacement, setup, or programming.
* Perform the Service Fast Learn Adapts (Programming and Relearning) .