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P0756



DTC P0751, P0756, or P0761

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



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

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

DTC P0761
- Shift Solenoid (SS) 3 Valve Performance - Stuck Off




Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The pressure switch manifold (PSM) is a multiple switch assembly made up of 3 normally open (N/O) pressure switches and 1 normally closed (N/C) pressure switch. Pressure switch 1 (PS1) monitors shift valve 1 positioning, pressure switch 2 (PS2) monitors shift valve 2 positioning and pressure switch 3 (PS3) monitors shift valve 3 positioning. The pressure switches communicate the positioning to the transmission control module (TCM). The position of the shift valves 1, 2, and 3 is controlled by 3 normally closed shift solenoids 1, 2, and 3 (SS1, SS2, and SS3). When energized, the shift solenoids direct control main pressure to shift valve 1, 2, or 3, which strokes the shift valve.


Conditions for Running the DTC


P0751
* Engine Running.
* Shift solenoid 1 (SS1) is commanded ON.



P0756
* Engine Running.
* Shift solenoid 2 (SS2) is commanded ON.



P0761
* Engine Running.
* Shift solenoid 3 (SS3) is commanded ON.



Conditions for Setting the DTC


P0751
* Engine Running.
* SS1 is commanded ON and PS1 remains OFF for up to 12 seconds depending on transmission fluid temperature.



P0756
* Engine Running.
* SS2 is commanded ON and PS2 remains OFF for up to 12 seconds depending on transmission fluid temperature.



P0761
* Engine Running.
* SS3 is commanded ON and PS3 remains OFF for up to 12 seconds depending on transmission fluid temperature.



Action Taken When the DTC Sets


P0751
* The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
* When in a forward range, the transmission will shift to another forward range, unless the transmission is compromised by overspeeding.
* When the shift selector is moved from a forward range to NEUTRAL or from a forward range to REVERSE, then the transmission will shift to NEUTRAL.
* If the shift selector is moved to forward, the transmission will shift to forward and if the selector is moved to REVERSE, the transmission will shift to REVERSE, unless the transmission is compromised by overspeeding or direction change, then a shift to NEUTRAL is made.
* DTC P0751 is stored in TCM history.
* The TCM freezes shift adapts.
* The TCM inhibits torque converter clutch (TCC) engagement.



P0756
* The TCM requests the ECM to illuminate the MIL.
* When in a forward range and shifting is completed, the transmission will shift to another forward range, unless the transmission is compromised by overspeeding or direction change, then the transmission will shift to NEUTRAL.
* If the shift selector is moved to forward, the transmission will shift to forward and if the selector is moved to REVERSE, the transmission will shift to REVERSE, unless the transmission is compromised by overspeeding or direction change, then a shift to NEUTRAL is made.
* DTC P0756 is stored in TCM history.
* The TCM freezes shift adapts.
* The TCM inhibits TCC engagement.



P0761
* The TCM requests the ECM to illuminate the MIL.
* When in a forward range and shifting is completed, the transmission will shift to another forward range, unless the transmission is compromised by overspeeding or direction change, then the transmission will shift to NEUTRAL.
* If the shift selector is moved to forward, the transmission will shift to forward and if the selector is moved to REVERSE, the transmission will shift to REVERSE, unless the transmission is compromised by overspeeding or direction change, then a shift to NEUTRAL is made.
* DTC P0761 is stored in TCM history.
* The TCM freezes shift adapts.
* The TCM inhibits TCC engagement.



Conditions for Clearing the DTC

DTCs P0751, P0756, and P0761 are Type A DTCs.


Diagnostic Aids

* If DTC P0701 is set in combination with either DTC P0751, P0756 or P0761, diagnose P0701 prior to proceeding to DTCs P0751, P0756 or P0761.
* You may have to drive the vehicle in order to experience a condition.



Reference Information
Schematic Reference

Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

* Transmission General Description (Transmission General Description)
* Transmission Component and System Description (Transmission Component and System Description)
* Electronic Component Description (Electronic Component Description)

Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Engine running, command the transmission through the forward ranges with a scan tool. Compare the TFP Switch 1, TFP Switch 2, and TFP Switch 3 parameters in each forward range with the PSM Logic table. Refer to Pressure Switch Manifold (PSM) Logic (Pressure Switch Manifold (PSM) Logic) .
2. 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. Inspect the transmission fluid level. Refer to Transmission Fluid Check (Transmission Fluid Check) .
2. Ignition OFF, disconnect the X175 harness connector at the transmission.
3. Ignition ON, engine OFF, connect a 3A fused jumper wire to the PS1 signal circuit terminal D to ground, PS2 signal circuit terminal F to ground, and PS3 signal circuit terminal E to ground. Verify with a scan tool the TFP Switch 1, TFP Switch 2, and TFP Switch 3 parameters changes from High to Low when the signal circuit is grounded.

• If not the specified value, test the affected pressure switch signal circuit for an open/high resistance. If circuits tests normal, replace the TCM.

4. Ignition OFF, connect the X175 harness connector to the transmission.
5. Remove the pressure switch module from the valve body. Leave the internal wire harness connected to the pressure switch manifold. Refer to Pressure Switch Manifold Replacement (Service and Repair) .
6. Connect a jumper wire to the base of the pressure switch module and ground.
7. Ignition ON, engine OFF, gently push on the PS1, PS2, and PS3 switches. Verify with a scan tool that TFP Switch 1, TFP Switch 2, and TFP Switch 3 parameters changed from High to Low.

• If not the specified value, test the internal wire harness circuits for an open/high resistance. If the circuits test normal, replace the pressure switch module.

8. If all circuits test normal, refer toControl Valve Body Assembly Disassemble (Overhaul) andControl Valve Body Cleaning and Inspection (Overhaul) .

• If valve body inspection is normal, replace the shift solenoid indicated by the DTC, refer toControl Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD) (Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD))Control Valve Solenoid Replacement (PCS1 and PCS2) (Control Valve Solenoid Replacement (PCS1 and PCS2)) .




Repair Instructions

Perform theDiagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Pressure Switch Manifold Replacement (Service and Repair)
* Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD) (Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD))Control Valve Solenoid Replacement (PCS1 and PCS2) (Control Valve Solenoid Replacement (PCS1 and PCS2))
* Wiring Harness Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for TCM replacement, setup, and programming



Repair Verification

If another DTC is present, refer toDiagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions) and perform the appropriate diagnostic procedure.

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