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DTC P0751 or P0752

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • 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
    • 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.
    • The transmission fluid temperature (TFT) is -7°C (19°F) or greater.
    • The engine speed is greater than 400 RPM for 5 seconds.
    • The output shaft speed is greater than 0 RPM or the throttle is greater than 0.5 percent.
    • The ignition voltage is 9.0 volts or greater.
    • The shift is complete.
    • The engine torque signal is valid.
    • The throttle position signal is valid.
    • The High-Side driver is enabled.

Conditions for Setting the DTC

P0751

The 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

The 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.
    • The TCM inhibits 1st gear.
    • The transmission control module (TCM) inhibits Neutral tick-over.

P0752

    • DTC P0752 is a type A DTC.
    • The TCM limits the transmission to 2nd range and reverse.
    • The TCM inhibits Tap Up/Down function.
    • The TCM inhibits manual shifting of forward gears.
    • The TCM disables neutral tick-over.
    • The TCM freezes adapts.
    • The 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 1

Connector End View Reference

    •  Component Connector End Views
    •  Inline Harness Connector End Views

Description and Operation

    •  Transmission General Description
    •  Transmission Component and System 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. Perform the Transmission Fluid Level and Condition Check to verify correct fluid level and condition.
  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. The DTCs should not set.
  3. Verify the scan tool Shift Solenoid Valve 1 and Gear Ratio parameters are correct for each gear range. Refer to Shift Solenoid Valve State and Gear Ratio .
  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 .

Circuit/System Testing
  1. Perform the Line Pressure Check . Verify the transmission line pressures are within the range specified in the Line PC Solenoid Valve Pressure table. Refer to Solenoid Valve Pressure : Gen 1 .
    2. ⇒If not within the specified range, refer to Fluid Pressure High or Low .
  2. Ignition OFF, remove the Q8 control solenoid valve assembly.
  3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test .
    4. ⇒If the Q8 control solenoid valve assembly does not pass the performance test, replace the Q8 control solenoid valve assembly.
  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.

DTCs

Component

Condition

P0751

P0752

Control Valve Body

Clutch select valve stuck - debris, sediment, binding, or scored bore

P0751

Control Valve Body

Bore Plug - Clutch Select Valve - Undersized bore plug causing a leak. Plug should be a valve fit in the bore.

P0751

Control Valve Body

Check ball #1 missing, damaged/malformed, Seat in the valve body damage/leaking.

P0751

P0752

Q8 Control Solenoid Valve Assembly
    • Not pressurising - Stuck OFF or leaking
    • Not exhausting - Stuck On
    • Control signal fluid supply leak - valve body filter plate assembly cracked or damaged gasket seal

P0751

P0752

Control Valve Body

Low and Reverse and 4-5-6 Clutch Regulator Valve Stuck or sticking - debris, sediment, binding, or scored bore

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

       Important: Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .

    • Refer to Control Module References for control solenoid valve assembly replacement, set-up, and programming.
    • Perform the Transmission Adaptive Values Learn following all transmission related repairs.
   


© Copyright Chevrolet. All rights reserved
   


© Copyright Chevrolet. All rights reserved