P0756

Shift Solenoid Valve State And Gear Ratio:

Circuit Description
The 2-3 Shift Solenoid Valve Assembly receives ignition voltage from a fused circuit 1039 and the ground path is provided by the Powertrain Control Module (PCM), depending on the solenoids commanded state. When the PCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure to the solenoid is exhausted. When the PCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure. The PCM monitors the commanded gear and the speed ratio in order to identify a malfunction in the 2-3 Shift Solenoid Valve Assembly. When the PCM detects a 1-2-2-1 or a 4-3-3-4 shift pattern, then DTC P0756 sets. DTC P0756 is a type A DTC.

Conditions for Setting the DTC
^ No TP DTCs P0122 or P0123.
^ No Vehicle Speed Sensor (VSS) DTCs P0502 or P0503.
^ No Torque Converter Clutch (TCC) solenoid DTCs P0740 or P0742.
^ No 1-2 solenoid electrical DTC P0753.
^ No 2-3 solenoid electrical DTC P0758.
^ No TCC PWM solenoid electrical DTC P1860.
^ The engine speed is greater than 500 RPM for 5 seconds.
^ Not in fuel shut off.
^ The transmission range indicates D4.
^ The vehicle speed is greater than 26 km/h (16 mph).
^ TFT is 20-130°C (68-266°F).
All of the above must occur and one of the following fail conditions must occur:
^ Fail case 3 and 4 (stuck on) must occur twice.
^ Fail case 1 and 3 or fail case 2 and 3 (stuck off) must occur twice.

Failure Criteria
Case 1
^ The PCM commands first gear for more than 1.5 seconds.
^ The TCC slip speed is -4,064 to 200 RPM.
^ Output speed is 900-1,600 RPM.
^ The speed ratio is 0.7-2.6.
^ Throttle position is more than 35%.
^ Engine torque is 54-271 N.m (40-200 ft lbs).
^ All of the above occurs for more than 1.5 seconds.

Case 2
^ The PCM commands second gear for more than 2 seconds.
^ The TCC slip speed is -4,064 to 0 RPM.
^ Output speed is 1000-2,100 RPM.
^ The speed ratio is 1.09-1.6.
^ Throttle position is more than 18%.
^ Engine torque is 54-271 N.m (40-200 ft lbs).
^ All of the above occurs for more than 2.0 seconds.

Case 3
^ The PCM commands third gear for 2.5-7.5 seconds.
^ The TCC slip speed is 600 RPM more than the slip speed in second gear.
^ The speed ratio is not 0.4 less than the last speed ratio in second gear.
^ Throttle position is 14-55% and constant by 7%.
^ Engine torque is 54-271 N.m (40-200 ft lbs).
^ All of the above occurs for more than 2.0 seconds.

Case 4
^ The PCM commands fourth gear for more than 1.0 second.
^ The TCC slip speed is 1,600-6,000 RPM.
^ Output speed is 1,500-2,800.
^ The speed ratio is 2-4.
^ Throttle position is more than 10%.
^ All of the above occurs for more than 1.5 seconds.

Action Taken When the DTC Sets
The PCM illuminates the Malfunction Indicator Lamp (MIL).

Conditions for Clearing the MIL/DTC
^ The PCM turns OFF the MIL after three consecutive trips without a failure reported.
^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

Diagnostic Aids
^ Check for PRNDL DTC P0705. DTC P0705 affects transmission operation. This may set DTC P0756 falsely.
^ Inspect the transmission fluid for sediment.
^ Inspect the transmission filter for debris.
^ Ensure that the scan tool commanded gear has correct solenoid states and ratio. Refer to Shift Solenoid Valve State and Gear Ratio table.

Test Description
The number below refers to the step number on the diagnostic chart.
3. Verify the DTC and inspect shift solenoid for sediment or missing O-ring.
4. If the problem is not corrected in step 3, replace the 2-3 shift solenoid.