For 1990-2009 cars
Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

### 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 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 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).

• | TFT is 20-130°C (68-266°F).

• | The transmission range indicates D4.

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 800-1700 RPM.

• | The speed ratio is 0.7-2.55.

• | Throttle position is more than 24%.

• | 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 14-45% 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.

• | 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.

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 data.

3. Record the DTC Freeze Frame and Failure Records.
4. Inspect for the following conditions:

• | Shift solenoid screen assy. 374 for sediment or debris.

• | 2-3 shift solenoid for a damaged or missing o-ring.

Refer to Unit Repair.

Was a condition found and corrected?

--

Go to Step 5

Go to Step 4

4 | Replace the 2-3 shift solenoid. Refer to Solenoids and Wiring Harness, Section 7. Is the replacement complete | -- | Go to Step 5 | --
5 | 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 (68-268°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).

• | All of the following pass criteria must be true:

#### Case 1

- | The PCM commands first gear for more than 2 seconds.

- | The throttle position is greater than 18%.

- | The speed ratio is 3-4.0.

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

- | The output speed is 800-1700 RPM.

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

#### Case 2

- | The PCM commands fourth gear.

- | 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 conditions 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