P0756
DTC P0756
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions 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 control solenoid valve assembly, which has no serviceable components. The SS valve 2 is a normally closed (NC) solenoid valve and controls fluid to the clutch select valve 3. The solenoid operates by the transmission control module (TCM) opening or closing the ground circuit. With the solenoid circuit grounded, solenoid on, the internal plunger moves and allows the metering ball to move away from the feed seat and against the exhaust seat, creating signal fluid pressure. The signal fluid acts against the clutch select valve 3 to overcome the valve spring force, moving it to the apply position.
Conditions for Running the DTC
* DTC P0101, P0102, P0103, P0106, P0107, P0108, P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723, or P182E is not set.
* Engine speed is 400 RPM or greater for 5.0 seconds.
* High side driver is enabled.
* Ignition voltage is 8.6 volts or greater.
* Throttle position signal is valid.
* Transmission fluid temperature (TFT) is 0°C (32°F) or greater.
Conditions for Setting the DTC
* Commanded Gear is 1st locked.
* Gearbox Slip is 200 RPM or greater for 3.5 seconds.
* If above conditions exist, the TCM will command second range. If the gear ratio is between 2.7 and 3.0 for 1.0 second, the counter will increment. DTC will set after 2 occurrences.
Action Taken When the DTC Sets
* DTC P0756 is a Type A DTC.
* TCM inhibits Tap Up/Down function.
* TCM inhibits manual shifting of forward gears.
* TCM commands maximum line pressure.
* TCM freezes transmission adaptive functions.
* TCM inhibits neutral idle.
* TCM limits the transmission to Reverse and 1st and 3rd gear operation.
Conditions for Clearing the DTC
DTC P0756 is a Type A DTC.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics Electrical Diagrams
Connector End View Reference
* Component Connector End Views A/C Compressor Clutch
* Inline Harness Connector End Views X101
Description and Operation
Transmission General Description Transmission General Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
Note:
If other DTCs are set, diagnose those DTCs first.
1. Verify correct fluid level and condition. Refer to Transmission Fluid Level and Condition Check Testing and Inspection.
2. Ignition ON, clear the TCM DTCs.
3. Engine running, brakes applied, transmission gear shift selector in Reverse. Shift to Drive and accelerate to 56 km/h (35 mph) with calculated throttle position greater than 15 percent. Perform this test 5 consecutive times. Verify DTC P0756 did not set.
• If DTC P0756 sets
Refer to Circuit/System Testing below.
• If DTC P0756 did not set
4. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.
Circuit/System Testing
1. Verify the transmission line pressures are within the ranges specified in the Line PC Solenoid Valve Pressure table. Refer to Line Pressure Check Line Pressure Check and Solenoid Valve Pressure Solenoid Valve Pressure.
• If line pressures are not within the specified ranges
Refer to Fluid Pressure High or Low Fluid Pressure High or Low.
• If line pressures are within the specified ranges
2. Ignition OFF, remove the Q8 control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement Service and Repair.
3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test. Test all solenoids on the Q8 control solenoid valve assembly. A pressure change should occur for each solenoid valve.
• If a pressure change does not occur for each solenoid
Replace the Q8 control solenoid valve assembly.
• If a pressure change occurs for each solenoid
4. Listed in the table below are conditions for each component that could set DTC P0756. Carefully inspect each component for that condition. Repair or replace as necessary.
Repair Instructions
Note:
* Perform the Reset Transmission Adapts Reset Transmission Adapts following all transmission related repairs.
* Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection Control Solenoid Valve and Transmission Control Module Assembly Inspection.
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Control Valve Upper Body Assembly Cleaning and Inspection Control Valve Upper Body Assembly Cleaning and Inspection
* Control Module References Control Module References for control solenoid valve assembly replacement, setup, or programming