P0756

Diagnostic Chart:

Descriptive:

Circuit Description

The Powertrain Control Module (PCM) monitors the commanded gear and speed ratio in order to identify a 2-3 Shift Solenoid Valve (2-3 SS Valve) problem. When the PCM detects a gear other than 1st gear when 1st gear is commanded, then DTC P0756 sets. When the PCM detects 1st gear when 4th gear is commanded, then DTC P0756 sets. DTC P0756 is a type A DTC.

Conditions for Setting the DTC

^ No Throttle Position (TP) DTCs P0122 or P0123.

^ No Vehicle Speed Sensor (VSS) DTCs P0502 or P0503.

^ No 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 vehicle speed is greater than 26 km/h (16 mph).

^ Transmission Fluid Temperature (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 must occur twice.

^ Fail case 1 and 3 or fail case 2 and 3 must occur three times.

Failure Criteria

Case 1

^ The PCM commands first gear for more than 2 seconds.

^ The TCC slip speed is -4064 to -300 RPM.

^ Output speed is 900-1600 RPM.

^ The speed ratio is 0.7-2.6.

^ Throttle position is more than 35%.

^ 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 -1000 to 100 RPM.

^ Output speed is 1000-2100 RPM.

^ The speed ratio is 1.09-1.6.

^ Throttle position is more than 18%.

^ 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 speed ratio in second gear.

^ Throttle position is 14-55% and constant by 7%.

^ All of the above occurs for more than 2.0 seconds.

Case 4

^ The PCM commands fourth gear for more than 1 second.

^ The TCC slip speed is 1600-6000 RPM.

^ Output speed is 1500-2800 RPM.

^ 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 DTC

^ The PCM turns OFF the MIL after three consecutive ignition cycles 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.

Test Description

The number below refers to the step number on the diagnostic table.

3. Once the DTC is verified, replace the 2-3 shift solenoid.