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.

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 100 RPM or greater.

Fail Case 2

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

DTC P0756 is a Type A DTC.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transmission General Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

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.

⇒	If the transmission fluid is low or discolored, refer to Transmission Fluid Replacement.

2. 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.
3. 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.
4. 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.

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.

⇒	If not within the specified range, repair as necessary. Refer to Fluid Pressure High or Low for further diagnosis.

3. Ignition OFF, remove the control solenoid (w/body and TCM) valve assembly.
4. 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.
5. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test. A pressure change should occur.

⇒	If a pressure change does not occur, replace the control solenoid (w/body and TCM) valve assembly.

6. Inspect for the following conditions and repair/replace as necessary:

•	The control valve lower body assembly for sticking valves, damage, scored bores, or debris

•	The clutch select valve 3 for damage

Important: 

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