P0757

Schematic:

Circuit Description with 4L30-E Automatic Transmission
The 2-3 Shift Solenoid (SS) valve is a normally open shift solenoid that controls the positioning of the 2-3 shift valve. When energized (on), the shift solenoid is closed and blocks D32/1-2 fluid from acting on the solenoid end of the 2-3 shift valve. When de-energized (off), the solenoid opens and D32/1-2 fluid pressure flows through the solenoid, acts on the solenoid end of the shift valve and moves the valve against spring force.

When the TCM detects a 1-2-2-1 shift pattern, then DTC P0757 will set. DTC P0757 is a type B DTC.

CONDITIONS FOR RUNNING THE DTC
^ Transmission is in drive (D).
^ No Trans Range Switch DTC P0705.
^ No Output Speed Sensor DTC P0722.
^ No 1-2 SS Valve DTC P0753.
^ No 2-3 SS Valve DTC P0758.
^ No TCM Internal - Watchdog Operation DTC P1600.
^ No TCM System Reset DTC P1625.
^ No TCC Enable Solenoid Circuit - Electrical DTC P0743.
^ No Throttle Position Signal DTC P1890.

All the above conditions must be present, plus one of the following conditions:

Condition 1:
^ The commanded gear is 3rd for greater than 0.7 seconds.
^ Throttle position is greater than 26.4 percent.
^ Engine speed is 3,104 to 4,192 RPM.
^ Transmission output speed is greater than 1,088 RPM.
^ Engine torque is greater than 50 N.m (68 lb ft).

Condition 2:
^ The commanded gear is 4th for greater than 0.5 seconds.
^ Throttle position is greater than 13.8 percent.
^ Engine speed is 3,008 to 6,016 RPM.
^ Transmission output speed is greater than 1,216 RPM.
^ Engine torque is greater than 0 N.m (0 lb ft).

CONDITIONS FOR SETTING THE DTC
DTC P0757 sets if the following conditions occur two times.

Condition 1:
TCC slip speed is 1,200 to 1,800 RPM for 3.0 seconds.

Condition 2:
TCC slip speed is 2,000 to 6,000 RPM for 1.3 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The TCM flashes the sport mode lamp and sends a MIL request to the ECM on the second consecutive drive trip that the diagnostic runs and fails. The ECM then illuminates the MIL.
^ The ECM records the operating conditions in the Freeze Frame at the time of the MIL request from the TCM.
^ The transmission operates in the default mode (maximum line pressure, command 4th gear, inhibit TCC, freeze shift adapts).

CONDITIONS FOR CLEARING THE MIL/DTC
^ The ECM turns off the MIL after three consecutive drive trips during which the TCM sends no MIL request.
^ A History DTC clears after forty consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission related diagnostic.
^ The scan tool clears the MIL/DTC.
^ The TCM cancels the DTC default mode actions when the ignition switch is Off long enough in order to power down the TCM.

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

TEST DESCRIPTION

Diagnostic Chart:

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