P0756

DTC P0756





Circuit Description
The 2-3 shift solenoid (SS) valve is a normally-open exhaust valve that, in conjunction with the 1-2 shift solenoid (SS) valve, allows 4 different shifting combinations. The 2-3 SS valve is attached to the control valve body within the transmission.
The transmission control module (TCM) monitors the actual gear ratio, and compares the actual gear ratio with the commanded gear ratio. DTC P0756 sets under 2 conditions:
^ A stuck ON 2-3 SS valve
^ A stuck ON 2-3 shift valve
When the TCM detects a 4-3-3-4 shift pattern, then DTC P0756 sets. DTC P0756 is a type A DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0756 2-3 Shift Solenoid (SS) Valve Performance - No First or Second Gear

Conditions for Running the DTC
^ No MAF DTCs P0101, P0102, or P0103.
^ No MAP DTCs P0107 or P0108.
^ No TP DTCs P0121, P0122 or P0123.
^ No VSS DTCs P0502 or P0503.
^ No ISS DTCs P0716 or P0717.
^ No SS electrical DTCs P1842, P1843, P1845, or P1847.
^ The engine run time is greater than 5 seconds.
^ The transmission fluid temperature (TFT) is 20 - 130°C (68 - 266°F).
^ The TP is greater than 8 percent.
^ The engine torque is greater than 30 Nm (22 ft. lbs.).
^ The vehicle speed is greater tan 8 km/h (5 mph).

Conditions for Setting the DTC
^ The TCM commands 1st gear and the gear ratio is 0.61:1-0.71:1, 4th gear, for 2 seconds.
^ The TCM commands 2nd gear and the gear ratio is 0.91:1-1.07:1, 3rd gear, for 3 seconds.

Action Taken When the DTC Sets
^ The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL).
^ The TCM inhibits 1st gear.
^ The TCM commands maximum line pressure.
^ The TCM turns off power to all solenoids.
^ The TCM freezes transmission adaptive functions.
^ The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
^ The TCM stores DTC P0756 in TCM history.

Conditions for Clearing the MIL/DTC
^ The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
^ A scan tool can clear the MIL/DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Diagnostic Aids
^ If you clear DTC P0756, and then cannot set DTC P0756 again, inspect for the following conditions:
^ Fluid contamination
^ Plugged fluid circuits
^ Restricted fluid circuits

Test Description





The numbers below refer to the step numbers on the diagnostic table.
3. This step verifies a 4-3-3-4 shift pattern.
4. This step tests for a mechanical or hydraulic condition causing the 2-3 SS valve to be stuck ON, or the circuit to be applied.