DTC P1751
| DTC P1751 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| 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 |
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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, P0741, P0742, P1751, P2763, or P2764 is not set.
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Current commanded range is not Neutral, Reverse, or 1st gear.
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The gear ratio is between 0.69-3.07.
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The engine speed is 400 RPM or greater for 5 seconds.
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The ignition voltage is 8.6 volts or greater.
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The transmission fluid temperature (TFT) is -7 to +130°C (19-266°F).
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The throttle position is 8 percent or greater.
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The engine torque is 80 Nm (59 lb ft) or higher.
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The engine speed is 500 RPM or greater.
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The vehicle speed is 16 km/h (10 mph) or greater.
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No upshift or downshift in process.
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The engine torque signal is valid.
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The throttle position signal is valid.
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The torque converter clutch (TCC) is commanded OFF.
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| 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 allows 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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
| 1. |
Engine idling in Park, with parking brake applied and drive wheels chocked.
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| 2. |
Perform the
Transmission Fluid Level and Condition Check
to verify correct fluid level and condition.
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| 3. |
Perform the Road Test . Verify the transmission operation performs as indicated, in the road test instructions. |
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| 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:
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Engine Speed
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Transmission ISS
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Transmission OSS
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Shift Solenoid Valve 1
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Gear Command
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| 5. |
After performing the above steps, verify that the dtc does not reset by operating the vehicle within the conditions for running fault codes (DTC). You may also operate the vehicle within the conditions you observe from the freeze frame/failure records. If the vehicle passes the circuit/system verification procedure, then stop. Do not perform the circuit/system test or component test as this may result in unnecessary part replacement. Refer to
Testing for Intermittent Conditions and Poor Connections
.
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| Circuit/System Testing |
| 1. |
Perform the
Line Pressure Check
. Check that the transmission's line pressure gauge is within the range specified in the table Line PC-solenoid valve pressure. See
Solenoid valve pressure
.
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| 2. |
If not within the specified ranges, refer to
Fluid Pressure High or Low
.
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| 3. |
Remove control solenoid valve assembly Q8 with ignition OFF. See
Replacing control solenoid valve assembly and transmission control module
.
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| 4. |
Perform the
Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test
.
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| 5. |
If the Q8 control solenoid valve assembly does not pass the performance test, replace the Q8 control solenoid valve assembly.
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| 6. |
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.
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| DTC | Component | Condition | ||||||
| P1751 | Upper Control Valve Body Assembly (349) | Clutch select valve 2 - spring broken, debris, valve stuck, binding, damaged valve, or scored bore | ||||||
| P1751 | Upper Control Valve Body Assembly (349) | #4 check ball for irregularities | ||||||
| P1751 | Upper Spacer Plate | Orifice # 14 blocked, obstructed, or irregular shaped | ||||||
| P1751 | Q8 Control Solenoid Valve Assembly (314) |
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| Repair Instructions |
| Note | ||
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Perform the Transmission Adaptive Values Learn following all transmission related repairs. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Valve Upper Body Assembly Cleaning and Inspection
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