6T70/6T75 - Automatic Transmission

DTC P0751

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 see if the valve is stuck OFF. When in first gear engine braking, if first gear ratio is not achieved in a predetermined period of time and the closest gear ratio detected if fourth, the TCM commands second gear and 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 transmission input speed is 50 RPM or less.
* 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 between 35-100 RPM within 0.5-1.0 seconds.

Action Taken When the DTC Sets

DTC P0751 is a Type C DTC.

Conditions for Clearing the DTC

DTC P0751 is a Type C DTC.

Diagnostic Aids

When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.

Special Tools Required

DT-47825 Control Solenoid Test Plate

Circuit/System Verification

1. Perform the Transmission Fluid Check. Transmission Fluid Check
2. Operate the vehicle in drive from a complete stop, with the calculated throttle position greater than 15 percent to obtain 56 km/h (35 mph) 2 times.

* If the DTC resets, go to Circuit/System Testing.

Circuit/System Testing

1. Perform the Line Pressure Check. Line Pressure Check

* If the pressure is out of specification correct that concern first.

2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Cleaning and retest the DTC as outlined in the Circuit/System Verification steps. Control Solenoid Valve and Transmission Control Module Assembly Cleaning

* If the DTC resets, continue on with testing.

3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection. Control Solenoid Valve and Transmission Control Module Assembly Inspection

* If a concern is found, repair or replace the control solenoid (w/body and TCM) valve assembly.

4. 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 shift solenoid 1 is found to be leaking or stuck OFF, replace the control solenoid (w/body and TCM) valve assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

1. Replace the control solenoid (w/body and TCM) valve assembly. Refer to Programming and Relearning for replacement, setup, or programming.
2. Perform the Service Fast Learn Adapts. Programming and Relearning