P0756

Diagnostic Chart:

CIRCUIT DESCRIPTION

The 2-3 Shift Solenoid is fed ignition voltage 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 that is fed 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 Powertrain Control Module (PCM) identifies a 2-3 Shift Solenoid Valve (2-3 SS Valve) performance condition by monitoring the commanded gear versus the gear ratio.

If the PCM detects the gear ratio outside the limits for a particular commanded gear, then DTC P0756 sets. DTC P0756 is a Type A DTC.

CONDITIONS FOR SETTING THE DTC

^ No TP DTCs P0121, P0122 or P0123 are set.

^ No VSS DTCs P0502 or P0503 are set.

^ No Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) DTCs P0716 or P0717 are set.

^ No 1-2 shift solenoid valve electrical DTC P0753 is set.

^ No 2-3 shift solenoid valve electrical DTC P0758 is set.

^ No Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) DTC P1810 is set.

^ No Torque Converter Clutch (TCC) PWM Sol. DTC P1860 is set.

^ The engine speed is greater than 500 RPM for 5 seconds, and not in fuel shut off.

^ The Automatic Transmission Fluid Temperature is greater than 20°C (68°F).

^ The transmission is not in Park or Neutral.

^ All of the above conditions are met, and Cases 1 and 2 are true once (stuck OFF), or Cases 3 and 4 are true twice (stuck ON).

Case 1

^ First gear is commanded.

^ The vehicle speed is greater than 11 km/h (7 mph).

^ The engine torque is 70-270 N.m (50-200 lb. ft).

^ The throttle position is greater than 8%.

^ The gear ratio indicates fourth gear (0.65:1-0.75:1).

^ Condition is met for 2 seconds.

Case 2

^ Second gear is commanded.

^ The vehicle speed is greater than 11 km/h (7 mph).

^ The engine torque is 70-270 N.m (50-200 lb. ft).

^ The throttle position is greater than 8%.

^ The gear ratio indicates third gear (0.95:1-1.05:1).

^ Condition is met for 1 second.

Case 3

^ Third gear is commanded.

^ The vehicle speed is greater than 11 km/h (7 mph).

^ The engine torque is 70-270 N.m (50-200 lb. ft).

^ The throttle position is greater than 8%.

^ The gear ratio indicates second gear (1.52:1 to 1.62:1).

^ Condition is met for 3 seconds.

Case 4

^ Fourth gear is commanded.

^ The vehicle speed is 56-132 km/h (35-82 mph).

^ The engine torque is 0-105 N.m (0-80 lb. ft).

^ The engine speed is less than 6700 RPM.

^ The throttle position is 7-40%.

^ The gear ratio is 1.05:1-2.97:1.

^ Condition is met for 3 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

^ The PCM commands 3rd gear.

^ The PCM commands maximum line pressure.

^ The PCM inhibits Torque Converter Clutch.

^ The PCM disables shift adapts.

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.

^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS

^ 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 the Shift Solenoid Valve State and Gear Ratio table.

TEST DESCRIPTION

The numbers below refer to the step numbers on the Diagnostic Table.

IMPORTANT: Do not drive the vehicle for an extended period of time, as additional internal damage may occur.

3. Set up data pairs on the scan tool. Drive the vehicle while commanding First gear with the scan tool.

4. This step verifies that the gear ratio indicates a Fourth gear start and the vehicle does not achieve First gear. The list of components should be inspected and repaired, if faulty.

6. This step verifies that the gear ratio indicates Third gear and the vehicle does not achieve Second gear. The list of components should be inspected and repaired, if faulty.

8. This step verifies that the gear ratio indicates Second gear and the vehicle does not achieve Third gear. The list components should be inspected and repaired, if faulty.

10. This step verifies that the gear ratio indicates First gear and the vehicle does not achieve Fourth gear. The list of components should be inspected and repaired, if faulty.