GM Service Manual Online
For 1990-2009 cars only

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

DTC P0752:  Shift Solenoid (SS) 1 Valve Performance - Stuck On

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 determine 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 is fourth, the TCM commands second gear and if second gear ratio is attained, this would indicate a stuck OFF SS valve 1 and the DTC sets.

Conditions for Running the DTC

P0751

    • The commanded gear slip or attained gear slip is at lease 100 RPM.
    • Intrusive Neutral Test neutral time is at least 3 seconds.
    • First gear locked is commanded.
    • The closest gear ratio is 4th gear.

P0752

    • Commanded gear has achieved 1st lock, 1st free-wheel, or 2nd gear.
    • Commanded gear is 3rd.

Conditions for Setting the DTC

P0751

Commanded gear equals first lock and gear ratio equals fourth and gear box slip is less than 100 RPM for 2.25 seconds.

P0752

Gear box slip is greater than 100 RPM for 3 seconds.

Action Taken When the DTC Sets

    • DTC P0751 is a Type C DTC.
    • DTC P0752 is a Type A DTC.

Conditions for Clearing the DTC

    • DTC P0751 is a Type C DTC.
    • DTC P0752 is a Type A DTC.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transmission General 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

Special Tools

    • DT-47825 Control Solenoid Test Plate
    • J 21867 Pressure Gage

Circuit/System Verification

  1. Perform the Transmission Fluid Check to verify correct fluid level and condition. The transmission fluid level should be within the crosshatch band and the transmission fluid should be red or dark brown.
  2. If the transmission fluid is low or discolored, refer to Transmission Fluid Replacement.
  3. Engine idling at operating temperature. Attempt to clean or free up a potential sticking valve with the scan tool Service Cleaning Procedure. Refer to Control Solenoid Valve and Transmission Control Module Assembly Cleaning for further instructions.
  4. From a stop, accelerate to 56 km/h (35 mph) with the calculated throttle position greater than 15 percent. Perform this test 2 times. The DTCs should not set.
  5. 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.

Circuit/System Testing

  1. Ignition OFF, remove the line pressure test hole plug and install the J 21867 to the transmission.
  2. Perform the Line Pressure Check. Verify the transmission line pressure gage is within the range specified in the Line PC Solenoid Valve Pressure table. Refer to Solenoid Valve Pressure.
  3. If not within the specified range, repair as necessary. Refer to Fluid Pressure High or Low for further diagnosis.
  4. Ignition OFF, remove the control solenoid (w/body and TCM) valve assembly.
  5. Install the DT-47825 to the control solenoid (w/body and TCM) valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test for detailed instructions.
  6. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test. A pressure change should occur.
  7. If a pressure change does not occur, replace the control solenoid (w/body and TCM) valve assembly.

Repair Instructions

Important: 

   • Perform the Service Fast Learn Adapts following all transmission related repairs.
   • Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, or programming