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 Descriptors
DTC P0751
-
Shift Solenoid 1 Valve Performance - Stuck Off
DTC P0752
-
Shift Solenoid 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 SS valve 1 is a normally closed (NC) solenoid valve and controls fluid pressure to the clutch select valve. When SS valve 1 is commanded on, fluid pressure acts on the clutch select valve, moving the valve to another position. Fluid from the R1/4-5-6 regulator valve flows though the clutch select valve and is directed to either the low and reverse clutch or the 4-5-6 clutch, depending on the position of the clutch select valve.
Conditions for Running the DTC
P0751
* 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.
* Transmission fluid temperature (TFT) is -7°C (19°F) or greater.
* Engine speed is greater than 400 RPM for 5 seconds.
* Output shaft speed is greater than 100 RPM or the throttle is greater than 0.5 percent.
* Ignition voltage is 9.0 volts or greater.
* Shift is complete.
* Engine torque signal is valid.
* Throttle position signal is valid.
* High-Side driver is enabled.
P0752
* 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.
* Transmission fluid temperature (TFT) is -7°C (19°F) or greater.
* Engine speed is greater than 400 RPM for 5 seconds.
* Output shaft speed is greater than 100 RPM or the throttle is greater than 0.5 percent.
* Ignition voltage is 9.0 volts or greater.
* Shift is complete.
* Throttle position signal is valid.
* High-Side driver is enabled.
Conditions for Setting the DTC
P0751
Transmission control module (TCM) detects gear slip greater than 400 RPM for 1.5 seconds with 1st gear commanded and the closest gear ratio is 4th gear. This must occur 8 times.
P0752
TCM detects gear slip greater than 400 RPM for 1.5 seconds when 3rd gear is commanded. This must occur 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 limits the transmission to 2nd range and reverse.
* TCM inhibits Tap Up/Down function.
* TCM inhibits manual shifting of forward gears.
* TCM disables neutral idle.
* TCM freezes adapts.
* TCM commands maximum line pressure.
Conditions for Clearing the DTC
P0751
DTC P0751 is a type B DTC.
P0752
DTC P0752 is a type A DTC.
Reference Information
Schematic Reference
Drive Range, First Gear Engine Braking (Gen 2/Hybrid)
Connector End View Reference
* Component Connector End Views Connector End Views By Name
* Inline Harness Connector End Views Connector End Views By Number
Description and Operation
* Transmission General Description Transmission General Description
* Transmission Component and System Description Transmission Component and System Description
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Programming and Relearning 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 Transmission Fluid Level and Condition Check.
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 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 (Gen 1) Solenoid Valve Pressure (Gen 1)Solenoid Valve Pressure (Gen 2) Solenoid Valve Pressure (Gen 2).
• If line pressure is not within the specified ranges
Refer to Fluid Pressure High or Low Fluid Pressure High or Low.
• If line pressure is 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 tested.
• 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 Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic repair.
Note:
Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection Control Solenoid Valve and Transmission Control Module Assembly Inspection.
* Refer to Control Module References Programming and Relearning for control solenoid valve assembly replacement, programming and setup.
* Perform the Transmission Adaptive Values Learn Programming and Relearning following all transmission related repairs.