P1751

DTC P1751

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 P1751
- Shift Valve 1 Performance

Circuit/System Description

The shift valve 1 (clutch select valve 2) is part of the lower control valve body. The shift valve 1 (clutch select valve 2) controls fluid to the R1 and 4-5-6 clutches. During this diagnostic test, intrusive actions are taken by the transmission control module (TCM) to test the clutch select valve 2 to see if the valve is stuck. The TCM commands the shift solenoid (SS) 1 ON to put pressure on the valve towards the spring and at the same time, elevates line pressure slightly to assist the spring side pressure. If the spring is broken, the valve will slip back towards the spring indicating a mechanical failure and the DTC will set.

Conditions for Running the DTC

* No ISS DTCs P0716 or P0717.
* No OSS DTCs P0722 or P0723.
* No TCC Performance DTCs P0741 or P0742.
* No TCC Electrical DTCs P2763, P2763, or P2764.
* The engine run time is greater than 5 seconds.
* The ignition voltage is between 8.6 volts and 19.0 volts.
* 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 N.m (59 lb ft).
* No upshift or downshift in process.
* The attained gear slip is equal to or greater than 70 RPM.

Conditions for Setting the DTC

The TCM detects attained gear slip is 100 RPM or greater for 0.5 seconds 5 times during the same ignition cycle.

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

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.

Circuit/System Verification

Operate the vehicle in drive with the calculated throttle position greater than 8 percent and ensure the TCC is commanded ON and OFF a minimum of 5 times.

If the DTC resets, go to Component Testing.

Component Testing

Inspect the lower control valve body for a stuck clutch select valve 2, a broken clutch select valve 2 spring, debris or damage.

If you found a valve body concern, repair or replace the lower control valve body as necessary.

Repair Instructions

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

1. Replace the control valve body. Refer to Control Valve Lower Body and Upper Body Replacement.
2. Perform the Service Fast Learn Adapts. Programming and Relearning