P1751
DTC P1751
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 P1751
- Shift Valve 1 Performance
Circuit/System Description
The shift solenoid (SS) 1 is part of the control solenoid valve assembly, which has no serviceable components. SS 1 provides fluid pressure to control the operation of the clutch select valve 2, which is located in the control valve lower body assembly. SS 1, in conjunction with clutch select valve 2, controls the pressure path to the reverse and low clutch and 4-5-6 clutch. A diagnostic test is performed by the transmission control module (TCM) to determine the state of the clutch select valve 2. During this diagnostic test, the TCM commands the SS 1 ON, supplying pressure to move the clutch select valve 2 toward its spring. At the same time, line pressure is elevated slightly to assist the spring side pressure. If the spring is broken, or the clutch select valve 2 cannot move due to another mechanical condition, the DTC will set.
Conditions for Running the DTC
* No DTCs 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, P0741, P0742, P1751, P2763, or P2764.
* Current gear is not 2nd.
* The engine speed is greater than 400 RPM for greater than 5 seconds.
* The ignition voltage is 8.6 volts or greater.
* The transmission fluid temperature (TFT) is 20-130°C (68-266°F).
* The calc. throttle position is 8 percent or greater.
* The engine torque is greater than 80 Nm (59 lb ft).
* The transmission input speed is greater than 1200 RPM.
* No upshift or downshift in process.
Conditions for Setting the DTC
The TCM detects attained gear slip is 100 RPM or greater for 1 second.
Action Taken When the DTC Sets
DTC P1751 is a Type B DTC.
Conditions for Clearing the DTC
DTC P1751 is a Type B DTC.
Diagnostic Aids
Before performing a road test, configure and setup the scan tool for snapshot mode. This will allow you to display, monitor, and verify multiple transmission data parameters at one time, after the road test.
Reference Information
Description and Operation
Transmission General Description Transmission General Description
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
1. Engine idling in Park, with parking brake applied and drive wheels chocked.
2. Perform the Transmission Fluid Level and Condition Check Transmission Fluid Level and Condition Check to verify correct fluid level and condition.
Note: Perform a scan tool snapshot, during the road test.
3. Perform the Road Test 6T70/6T75 - Automatic Transmission. Verify the transmission operation performs as indicated in the road test instructions.
4. Review the scan tool snapshot transmission data parameters. Verify the engine and transmission data parameters display the correct values in all forward gear ranges:
* Engine Speed
* Vehicle Speed
* Transmission ISS
* Transmission OSS
* Shift Solenoid 1
* Commanded Gear
5. 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. Perform the Line Pressure Check Line Pressure Check. Verify the transmission line pressure gauge is within the range specified in the Line PC Solenoid Valve Pressure table.
• If not within the specified ranges, refer to Fluid Pressure High or Low Fluid Pressure High or Low.
2. Ignition OFF, remove the 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.
• If the control solenoid valve assembly does not pass the performance test, replace the control solenoid valve assembly.
4. Listed in the chart below, are conditions for each component that could set DTC P1751. Carefully inspect each component for that condition. Repair or replace as necessary.
Repair Instructions
Note: Perform the Reset Transmission Adapts Programming and Relearning following all transmission related repairs.
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Control Valve Upper Body Assembly Cleaning and Inspection 50. Control Valve Upper Body Assembly Cleaning and Inspection