P0751
DTC P0751 or P0752
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 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 control solenoid valve assembly, which has no serviceable components. The solenoid operates by the transmission control module (TCM) opening or closing the ground circuit. With the solenoid circuit open, the plunger forces the metering ball against the actuator feed limit seat, blocking the flow and any existing pressure is exhausted through the exhaust port. With the solenoid circuit grounded, solenoid on, the internal plunger moves, allowing the metering valve to move away from the actuator feed limit seat and against the exhaust seat, creating signal fluid pressure. The signal fluid pressure acts against the clutch select valve 2 to overcome the valve spring force, moving the valve to the apply position. Fluid pressure from the R1/4-5-6 regulator valve flows through clutch select valve 2 and is directed to either the low and reverse clutch or the 4-5-6 clutch, depending on the position of clutch select valve 2.
Conditions for Running the DTC
P0751
* Ignition voltage is 8.6 volts or greater.
* Engine speed is 400 RPM or greater for 5.0 seconds.
* Throttle position signal is valid.
* Engine torque signal is valid.
* High side driver is enabled.
* Transmission fluid temperature (TFT) is 0°C (32°F) or greater.
* 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.
P0752
* Ignition voltage is 8.6 volts or greater.
* Engine speed is 400 RPM or greater for 5.0 seconds.
* High side driver is enabled.
* Throttle position signal is valid.
* TFT is 0°C (32°F) or greater.
* 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.
Conditions for Setting the DTC
P0751
Commanded gear equals first lock, the gear ratio is 1.34-1.48, and gear box slip is 200 RPM or greater for 0.3 second, 8 times.
P0752
Transmission has achieved 1st Locked, 1st Free-Wheel, or 2nd, the 456/R1 pressure switch is pressurized, 3rd gear is commanded, and gear box slip is 200 RPM or greater for 2.0 seconds, 5 times.
Action Taken When the DTC Sets
P0751
* DTC P0751 is a Type B DTC.
* TCM inhibits 1st gear.
* TCM inhibits neutral idle.
P0752
* DTC P0752 is a Type A DTC.
* TCM freezes transmission adaptive functions.
* TCM commands maximum line pressure.
* TCM inhibits Tap Up/Down function.
* TCM inhibits manual shifting of forward gears.
* TCM limits the transmission to Reverse, 1st, and 3rd gear operation.
Conditions for Clearing the DTC
P0751
DTC P0751 is a Type B DTC.
P0752
DTC P0752 is a Type A DTC.
Diagnostic Aids
Before performing a road test, configure and setup the scan tool for snapshot mode. This allows you to display, monitor, and verify multiple transmission data parameters at one time, after the road test.
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 transmission fluid level and condition. Refer to Transmission Fluid Level and Condition Check Testing and Inspection.
2. From a stop, accelerate to 72 km/h (45 mph) with the calculated throttle position greater than 15 percent. Perform this test 8 times. DTCs P0751 or P0752 should not set
• If DTC P0751 or P0752 sets
Refer to Circuit/System Testing below.
• If DTC P0751 or P0752 does not set
3. 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.
• If a pressure change does not occur for each solenoid tested
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 P0751 or P0752. 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 Module References Control Module References for control solenoid valve assembly replacement, setup, or programming