For 1990-2009 cars

### 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 Descriptor

DTC P0751: Shift Solenoid (SS) 1 Valve Performance - Stuck Off

### Circuit/System Description

The shift solenoid (SS) valve 1 is part of the lower control valve body. The SS valve 1 is a normally closed (NC) solenoid valve and controls fluid to the clutch select valve 3- and related clutches. During this diagnostic test, intrusive actions are taken by the transmission control module (TCM) to test the SS valve 1 to determine if the valve is stuck OFF. When attempting first gear engine braking, if first gear ratio is not achieved in a predetermined period of time and the closest gear ratio detected is fourth, the TCM will command second gear. If second gear ratio is attained this indicates a stuck OFF SS valve 1 and the DTC will set.

### Conditions for Running the DTC

• | The vehicle speed is 25 km/h (16 mph) or less.

• | First gear locked is commanded.

• | The closest gear ratio is 4th gear.

### Conditions for Setting the DTC

Commanded gear equals first lock and gear ratio equals fourth and gear box slip is less than 100 RPM for 0.125 seconds.

### Action Taken When the DTC Sets

• | DTC P0751 is a Type B DTC.

• | The TCM inhibits 1st gear.

### Conditions for Clearing the DTC

DTC P0751 is a Type B DTC.

### Reference Information

#### Schematic Reference

Drive Range, First Gear Engine Braking

#### Connector End View Reference

Component 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

#### Special Tools

• | DT-48616 Control Solenoid Test Plate

• | DT-48616-10 Adapter Harness

• | EN-21867 Pressure Gage

For equivalent regional tools, refer to Special Tools.

### Circuit/System Verification

1. Perform the Transmission Fluid Check to verify correct fluid level and condition. The transmission fluid level should be within the crosshatch band and the transmission fluid should be red or dark brown.

⇒ | If the transmission fluid is low or discolored, refer to Transmission Fluid Replacement.

2. Engine idling at operating temperature. Attempt to clean or free up a potential sticking valve with the scan tool Service Cleaning Procedure. Refer to Control Solenoid Valve and Transmission Control Module Assembly Cleaning for further instructions.
3. From a stop, accelerate to 56 km/h (35 mph) with the calculated throttle position greater than 15 percent. Perform this test 2 times. The DTCs should not set.
4. 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. Ignition OFF, remove the line pressure test hole plug and install the EN-21867 gage to the transmission.
2. Perform the Line Pressure Check. Verify the transmission line pressure gage is within the range specified in the Line PC Solenoid Valve Pressure table. Refer to Solenoid Valve Pressure.

⇒ | If not within the specified range, repair as necessary. Refer to Fluid Pressure High or Low for further diagnosis.

3. Ignition OFF, remove the control solenoid (w/body and TCM) valve assembly.
4. Install the DT-48616 test plate to the control solenoid (w/body and TCM) valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test for detailed instructions.
5. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test. A pressure change should occur.

⇒ | If a pressure change does not occur, replace the control solenoid (w/body and TCM) valve assembly.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

• | Refer to Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.

• | Perform the Service Fast Learn Adapts following all transmission related repairs.