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 P0756:  Shift Solenoid (SS) 2 Valve Performance - Stuck Off

Circuit/System Description

The shift solenoid (SS) valve 2 is part of the lower control valve body. The SS valve 2 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 2 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, the TCM commands second gear and if second gear ratio is attained this indicates a stuck OFF SS valve 2 and the DTC will set.

Conditions for Running the DTC

    • No DTCs P0716 or P0717.
    • No DTC P0722 or P0723.
    • No DTCs P1825 or P1915.
    • Calculated throttle position is equal to or greater than 10 percent.
    • Engine torque is between 120-1,492 N·m (89-1,100 lb ft).
    • Transmission fluid temperature (TFT) is equal to or greater than 0°C (32°F).

Conditions for Setting the DTC

    • The TCM detects second gear ratio is achieved.
    • Fail Case 1 and Fail Case 2 must occur in sequential order.

Fail Case 1

Commanded gear equals first lock or first freewheel and gearbox slip is equal or greater than 100 RPM.

Fail Case 2

Commanded gear equals second and second gear box slip is less than or equal to 35 RPM or gear box slip is equal to or less than 100 RPM and shift time-out occurs and PC Sol 4 commanded pressure is at maximum.

Action Taken When the DTC Sets

DTC P0756 is a Type A DTC.

Conditions for Clearing the DTC

DTC P0756 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

Connector End View Reference

    •  Automatic Transmission Inline 16-Way Connector End View
    •  Automatic Transmission Internal Connector End Views
    •  Automatic Transmission Related 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 Control Solenoid Test Plate

Circuit/System Verification

  1. Perform the Transmission Fluid Check .
  2. Operate the vehicle in drive with the calculated throttle position greater than 15 percent to obtain 56 km/h (35 mph) 2 times.
  3. If the DTC resets, go to Circuit/System Testing.

Circuit/System Testing

  1. Perform the Line Pressure Check .
  2. If the pressure is out of specification correct that concern first.
  3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Cleaning and retest the DTC as outlined in the Circuit/System Verification steps.
  4. If the DTC resets, continue on with testing.
  5. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .
  6. If a concern is found, repair or replace the control solenoid (w/body and TCM) valve assembly.
  7. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test .
  8. If the solenoid 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.

  1. Replace the control solenoid (w/body and TCM) valve assembly. Refer to Control Module References for replacement, setup, or programming.
  2. Perform the Service Fast Learn Adapts .