For 1990-2009 cars

## DTC P0756 2-3 (B) Shift Solenoid Performance Buick Built Before 6/17/96

OBD II Symbol Description Notice
Automatic Transmission Controls Schematics
Automatic Transmission Components

### 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 DTC P0740.

• | No TCC stuck on DTC P0742.

• | No 1-2 SS electrical DTC P0753.

• | No 2-3 SS electrical DTC P0758.

• | No TCC PWM solenoid DTC P1864.

• | 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).

• | The transmission fluid temperature is 20-130°C (68-266°F).

• | The transmission gear range switch is D4.

• | All of the above conditions are met, and cases 3 and 4 occur twice.

• | All of the above conditions are met, and cases 1 and 3 occur three times.

• | All of the above conditions are met, and 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 0.7-2.55.

- | 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 -1000-100 RPM.

- | The output speed is 1000-2100 RPM.

- | The speed ratio is 1.09-1.6.

- | 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 500 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 of the above occurs for more than 2 seconds.

#### Case 4

- | 4th gear is commanded for more than 1 seconds.

- | 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 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 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.

• | Refer to Shift Solenoid Valve State and Gear Ratio table.

### Test Description

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

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

#### DTC P0756 2-3 Shift Solenoid Performance (Early Buick)

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (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.

Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM.

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:

• | The transmission fluid temperature is 20-130°C (68-266°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 more than 18%.

- | The speed ratio is 2.94-4.00.

- | The TCC slip speed is 150-2700 RPM.

- | The output speed is 900-1600 RPM.

- | All of these occur for more than 1.5 seconds.

#### Case 2

- | Fourth gear is commanded.

- | The throttle position is more than 14%.

- | The speed ratio is 0.65-0.98.

- | The TCC slip speed is -20 to 100 RPM.

- | The output speed is 1500-2800 RPM.

- | All of these 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:

First and Second Gear Only

Third and Fourth Gear Operation

Fourth Gear Starts

## DTC P0756 2-3 (B) Shift Solenoid Performance All Other Applications

OBD II Symbol Description Notice
Automatic Transmission Controls Schematics
Automatic Transmission Components

### 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 Sol. Valve DTC P0740.

• | No TCC Stuck On DTC P0742.

• | No 1-2 SS Electrical DTC P0753.

• | No 2-3 SS Electrical DTC P0758.

• | No TCC PWM Sol. Valve DTC P1864.

• | 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).

• | The transmission fluid temperature is 20-130°C (68-266°F).

• | The transmission gear range switch is D4.

• | All the above conditions are met, and cases 3 and 4 occur twice.

• | All the above conditions are met, and cases 1 and 3 occur three times.

• | All the above conditions are met, and 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 -100 RPM.

- | The output speed is 800-1500 RPM.

- | The speed ratio is 0.7-2.8.

- | 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 -1000-100 RPM.

- | The output speed is 1000-2100 RPM.

- | The speed ratio is 1.09-1.6.

- | 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 500 RPM more than the slip speed in 2nd gear.

- | The speed ratio is not 0.5 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 seconds.

#### Case 4

- | 4th gear is commanded for more than 1.5 seconds.

- | 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 occurs for more than 2 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 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.

• | Refer to Shift Solenoid Valve State and Gear Ratio table.

### Test Description

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

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 Powertrain On Board Diagnostic (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.

Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM.

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:

• | The transmission fluid temperature is 20-130°C (68-266°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 more than 18%.

- | The speed ratio is 3-4.

- | The TCC slip speed is 200-2700 RPM.

- | The output speed is 800-1500 RPM.

- | All of these occur for more than 1.5 seconds.

#### Case 2

- | Fourth gear is commanded.

- | The throttle position is more than 14%.

- | The speed ratio is 0.65-0.98.

- | The TCC slip speed is -20 to 100 RPM.

- | The output speed is 1500-2800 RPM.

- | All of these 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:

First and Second Gear Only

Third and Fourth Gear Only

Fourth Gear Starts