GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1997 🢒 Skylark 🢒 DTC 🢒 DTC P0756 2-3 (B) Shift Solenoid Performance

DTC P0756 2-3 (B) Shift Solenoid Performance 3.1L VIN M


Object Number: 28123 Size: MF
OBD II Symbol Description Notice
Automatic Transmission Controls Schematics 3.1L VIN M
Automatic Transmission Components 3.1L VIN M

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.

If the PCM detects a gear other than 1st gear when 1st gear is commanded, then DTC P0756 sets. If 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 TP DTCs P0122 or P0123
    • No 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 TFT is 20-130°C (68-266°F).
    • The vehicle speed is more than 26 km/h (16 mph).
    • The engine speed is more than 500 RPM for 5 seconds.
    • The engine is not in fuel shut off.
    • All the above, and one of the following conditions must be true
       - Fail cases 3 and 4 occur twice.
       - Fail cases 1 and 3 occur three times.
       - Fail cases 2 and 3 occur three times.

Case 1

   • 1st gear is commanded for more than 2 seconds.
   • TCC slip speed is -4064 to -300.
   • The output speed is 900-1600 RPM.
   • The speed ratio is 0.6-2.3.
   • The throttle position is more than 35%.
   • All of the above occurs for more than 1.5 seconds.

Case 2

   • 2nd gear is commanded for more than 2 seconds.
   • The TCC slip speed is -1000 to 100 RPM.
   • The output speed is 1000-2100 RPM.
   • The speed ration is 0.97-1.45.
   • The throttle position is more than 18%.
   • All of the above occurs for more than 2 seconds.

Case 3

   • 3rd gear is commanded for 2.5-7.5 seconds.
   • The TCC slip speed is 600 RPM more than the slip speed in 2nd gear.
   • The speed ratio is not 0.4 less than the speed ratio in 2nd gear.
   • The throttle position is 14-45% and constant by 7%.
   • All the above occurs for more than 2 seconds.

Case 4

   • 4th gear is commanded for more than 1 second.
   • The TCC slip speed is 1600-6000 RPM.
   • The output speed is 1500-2800 RPM.
   • The speed ratio is 2-4.
   • The throttle position is more than 10%.
   • All of the above for more than 1.5 seconds.

Action Taken When the DTC Sets
    • The PCM defaults the transmission to 3rd gear.
    • The PCM inhibits TCC engagement.
    • The PCM illuminates the Malfunction Indicator Lamp (MIL).

Conditions for Clearing the MIL/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.
    • 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
    • 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.
    • Refer to Shift Solenoid Valve State and Gear Ratio table.

Test Description

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

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

DTC P0756 2-3 Shift Solenoid Performance

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to OBD System Check

2

Have you performed the fluid checking procedure?

--

Go to Step 3

Go to Transmission Fluid Check

3
  1. Install the scan tool.
  2. With the engine OFF, turn the ignition switch to the RUN position.

    3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function erases the stored Freeze Frame and Failure Records.

  3. Record the DTC Freeze Frame and Failure Records.
  4. After verifying that the DTC has set, replace the 2-3 Solenoid. Refer to Solenoids and Wiring Harness, in On-Vehicle Service.

Is the replacement complete?

--

Go to Step 4

--

4

In order to verify your repair, perform the following procedure:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
    4. • The transmission fluid temperature is 20-130°C (68-268°F).
    • The engine speed is more than 500 RPM for 5 seconds.
    • The vehicle is not in fuel shut off.
    • Gear range is D4.
    • The vehicle speed is more than 26 km/h (16 mph).
    • Both of the following cases must be true:
    • Case 1
       - First gear is commanded for more than 2 seconds.
       - The throttle position is greater than 18%.
       - The speed ratio is 2.7-4.
       - The TCC slip speed is 200-2700 RPM.
       - Output speed is 900-1600 RPM.
       - All of the above occurs for more than 1.5 seconds.
    • Case 2
       - Fourth gear is commanded.
       - The throttle position is greater than 14%.
       - The speed ratio is 0.58-0.88.
       - The TCC slip speed is -20 to 100 RPM.
       - The output speed is 1500-2800 RPM.
       - All of the above occurs for for more than 3 seconds.
  4. Select Specific DTC. Enter DTC P0756.

Has the test run and passed?

--

System OK

Begin the diagnosis again. Go to System Diagnosis Charts:

1st and 2nd Gear Only (1-2-2-1)

3rd and 4th Gear Operation (4-3-3-4) 2nd Gear Downshifts Attainable Through Manual Gear Ranges

DTC P0756 2-3 (B) Shift Solenoid Performance 2.4L VIN T


Object Number: 28123 Size: MF
OBD II Symbol Description Notice
Automatic Transmission Controls Schematics 3.1L VIN M
Automatic Transmission Components 3.1L VIN M

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.

If the PCM detects a gear other than 1st gear when 1st gear is commanded, then DTC P0756 sets. If 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 ECT DTCs P0112, P0113, P0117, or P0778
    • No TP DTCs P0122 or P0123
    • No VSS DTC 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 IAT DTCs P1111, P1112, P1114, or P1115.
    • No TCC PWM Solenoid Electrical DTC P1860.
    • The transmission range is D4.
    • The Engine Run Time is less than 3 minutes, and the IAT is 40-120°C (104-248°F) at startup.
    • The Engine Run Time is more than 3 minutes, and the ECT is 40-120°C (104-248°F).
    • The vehicle speed is more than 26 km/h (16 mph).
    • The engine speed is more than 500 RPM for 5 seconds.
    • The engine is not in fuel shut off.
    • The MAP is 20-100 kPa (3-14 psi).
    • All of the above must be true, and one of the following must occur:
       - Fail cases 3 and 4 occur twice.
       - Fail cases 1 and 3 occur three times.
       - Fail cases 2 and 3 occur three times.

Case 1

   • 1st gear is commanded for more than 2 seconds.
   • The TCC slip speed is -4064 to -300 RPM.
   • The Output speed is 900-1600 RPM.
   • The speed ratio is 0.76-3.00.
   • The throttle position is more than 35%.
   • All of the above occurs for more than 1.5 seconds.

Case 2

   • 2nd gear is commanded for more than 2 seconds.
   • The TCC slip speed is -1000 to -200 RPM.
   • The output speed is 1000-2600 RPM.
   • The speed ratio is 1.1-1.6.
   • The throttle position is more than 18%.
   • All of the above occurs for more than 2 seconds.

Case 3

   • 3rd gear is commanded for 2.5-7.5 seconds.
   • The TCC slip speed is 600 RPM more than the slip speed in 2nd gear.
   • The speed ratio is not more than 0.4 less than the speed ratio in 2nd gear.
   • The throttle position is 14-45% and constant by 7%.
   • All of the above occurs for more than 2.5 seconds.

Case 4

   • 4th gear is commanded for more than 1 second.
   • The TCC slip speed is 1600-6000 RPM.
   • The output speed is 1500-2800 RPM.
   • The speed ratio is 2-4.
   • The throttle position is more than 14%.
   • 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).
    • The transmission defaults to 3rd gear.
    • The PCM inhibits TCC operation.

Conditions for Clearing the MIL/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.
    • 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
    • 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.
    • Refer to Shift Solenoid Valve State and Gear Ratio table.

Test Description

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

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

DTC P0756 2-3 Shift Solenoid Performance

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to OBD System Check

2

Have you performed the fluid checking procedure?

--

Go to Step 3

Go to Transmission Fluid Check

3
  1. Install the scan tool.
  2. With the engine OFF, turn the ignition switch to the RUN position.

    3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data.

  3. Record the DTC Freeze Frame and Failure Records.
  4. After verifying that the DTC has set, replace the 2-3 Solenoid. Refer to Solenoids and Wiring Harness, in On-Vehicle Service.

Is the replacement complete?

--

Go to Step 4

--

4

In order to verify your repair, perform the following procedure:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
    4. • The Engine Run Time is less than 3 minutes, and the IAT is 40-120°C (104-248°F) at startup.
    • The Engine Run Time is more than 3 minutes, and the ECT is 40-120°C (104-248°F) at startup.
    • The engine speed is more than 500 RPM for 5 seconds.
    • The engine is not in fuel shut off.
    • The gear range is D4.
    • The vehicle speed is greater than 26 km/h (16 mph).
    • All of the following pass criteria must be true:

    Case 1

       - First gear is commanded for more than 2 seconds.
       - The throttle position is more than 18%.
       - The speed ratio is 3.4-5.0.
       - The TCC slip speed is 250-2700 RPM.
       - The output speed is 900-1600 RPM.
       - All of the above occur for more than 1.5 seconds.

    Case 2

       - Fourth gear is commanded.
       - The throttle position is more than 8%.
       - The speed ratio is 0.76-1.1.
       - The TCC slip speed is -20 to 100 RPM.
       - The output speed is 1500-2800 RPM.
       - All of the above occur for more than 3 seconds.
  4. Select Specific DTC. Enter DTC P0756.

Has the test run and passed?

--

System OK

Begin the diagnosis again. Go to System Diagnosis Charts:

1st and 2nd Gear Only (1-2-2-1)

3rd and 4th Gear Operation (4-3-3-4) 2nd Gear Downshifts Attainable Through Manual Gear Ranges