P0751

DTC P0751

Circuit Description
The 1-2 Shift Solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The 1-2 SS valve is a normally-open exhaust valve that is used with the 2-3 SS valve, in order to allow four different shifting combinations. When the PCM detects a 2-2-3-3 shift pattern, then DTC P0751 sets. DTC P0751 is a type B DTC.

Conditions for Running the DTC
^ No TP sensor DTCs P0122 or P0123.
^ No VSS assembly DTCs P0502 or P0503.
^ No TCC solenoid valve DTC P0740.
^ No TCC stuck ON DTC P0742.
^ No 1-2 SS valve DTC P0753.
^ No 2-3 SS valve DTC P0758.
^ No 3-2 SS valve assembly DTC P0785.
^ No TFP manual valve position switch DTC P1810.
^ No TCC PWM solenoid valve DTC P1860.
^ The engine speed is greater than 450 RPM for 5 seconds.
^ The engine is not in fuel cutoff.
^ The gear range is D4.
^ The TP angle is greater than 10 percent.
^ The transmission fluid temperature is 20 - 130°C (68 - 266°F).
^ The system voltage is 10 - 18 volts.
^ The engine torque is 68 - 542 Nm (50 - 400 ft. lbs.).
^ The transmission output speed is 150 RPM or greater.

Conditions for Setting the DTC
DTC P0751 sets if both of the following conditions occur twice: Condition 1
^ The PCM commands first gear for 2 seconds.
^ The estimated gear ratio is 1.2-1.825.
^ All conditions are met for 0.5 seconds. Condition 2
^ The PCM commands fourth gear for 1 second.
^ The estimated gear ratio is 0.95-1.15.
^ All conditions are met for 6 seconds.

Action Taken When the DTC Sets
^ The PCM illuminates the Malfunction Indicator Lamp (MIL).
^ The PCM commands D2 line pressure.
^ The PCM freezes shift adapts from being updated.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
^ The PCM stores DTC P0751 in PCM history.

Conditions for Clearing the MIL/DTC
^ The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ A scan tool can clear the MIL/DTC.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.

The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids
^ Verify that the transmission meets the specifications in the Shift Speed table.
^ Other internal transmission failures may cause more than one shift to occur.
^ Refer to the Shift Solenoid Valve State and Gear Ratio table.

Test Description
The number below refers to the step number on the diagnostic table.
2. This step tests that: the PCM commanded all shifts, that aft shift solenoid valves responded correctly, but that all the shifts did not occur.

Steps 1 - 5:

DTC P0751