Circuit Description
The 2-3 shift solenoid valve controls the fluid acting on the 2-3 shift
valve. The PCM commands the solenoid ON or OFF by controlling the ground on
the circuit. When the solenoid is OFF, line pressure exhausts through the
solenoid valve, allowing the 2-3 shift valve to be held by spring pressure
in the third and fourth gear position. When the solenoid is ON, the exhaust
flow is blocked, allowing line pressure to the 2-3 shift valve. This moves
the 2-3 shift valve to the first and second gear position.
When the PCM detects a 1-2-2-1 or a 4-3-3-4 shift pattern under
test conditions, without an electrical malfunction, then DTC P0756
sets. DTC P0756 is a type A DTC.
Conditions for Running the DTC
| • | No TP DTCs P0122 or P0123. |
| • | No VSS DTCs P0502 or P0503. |
| • | No 1-2 solenoid electrical DTC P0753. |
| • | No 2-3 solenoid electrical DTC P0758. |
| • | No TCC solenoid DTCs P0740 or P0742. |
| • | No TCC PWM solenoid electrical DTC P1860. |
| • | The engine speed is greater than 500 RPM for 5 seconds. |
| • | The transmission range indicates D4. |
| • | The vehicle speed is greater than 26 km/h (16 mph). |
| • | TFT is 20-130°C (68-266°F). |
Conditions for Setting the DTC
DTC P0756 sets if one of the following conditions is true:
| • | Fail case 3 and 4 (stuck on) occurs twice. |
| • | Fail case 1 and 3 or fail case 2 and 3 (stuck off) occurs twice. |
Failure Criteria
Case 1
| • | Output speed is 900-1,600 RPM. |
| • | The speed ratio is 0.7-2.6. |
| • | Throttle position is more than 35%. |
| • | Engine torque is 54-271 N·m(40-200 ft lbs). |
| • | The PCM commands first gear for more than 1.5 seconds. |
| • | The TCC slip speed is -4,064 to -200 RPM. |
All of the above occurs for more than 1.5 seconds.
Case 2
| • | Output speed is 1,000-2,100 RPM. |
| • | The speed ratio is 1.09-1.6. |
| • | Throttle position is more than 18%. |
| • | Engine torque is 54-271 N·m (40-200 ft lbs). |
| • | The PCM commands second gear for more than 2 seconds. |
| • | The TCC slip speed is -4,064 to 0 RPM. |
All of the above occurs for more than 2.0 seconds.
Case 3
| • | Throttle position is 14-55% and constant within + or -7%. |
| • | Engine torque is 54-271 N·m (40-200 ft lbs). |
| • | The PCM commands third gear for 2.5-7.5 seconds. |
| • | The TCC slip speed is at least 600 RPM more than the last
slip speed in second gear. |
| • | The speed ratio is not 0.4 less than the last speed ratio
in second gear. |
All of the above occurs for more than 2.0 seconds.
Case 4
| • | The PCM commands fourth gear for more than 1.0 second. |
| • | Throttle position is more than 10%. |
| • | Output speed is 1,500-2,800. |
| • | The speed ratio is 2-4. |
| • | The TCC slip speed is 1,600-6,000 RPM. |
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 PCM commands third gear only. |
| • | The PCM inhibits TCC operation. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL during the third consecutive trip in
which the diagnostic test runs and passes. |
| • | A scan tool clears the DTC from PCM history. |
| • | The PCM clears the DTC from the PCM history if the vehicle completes
40 consecutive warm-up cycles without an emission related diagnostic fault
occurring. |
| • | 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 and filter for sediment or debris. |
Test Description
The number below refers to the step number on the diagnostic chart.
-
Verify the DTC and inspect shift solenoid and shift valve for sediment
or missing O-ring.
-
If the problem is not corrected in step 3, replace the
2-3 shift solenoid.
DTC P0756 2-3 Shift Solenoid Valve-- 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 Transmission Fluid Checking Procedure?
| --
|
Go to Step 3
| Go to
Transmission Fluid Check
|
3
|
- Install the Scan Tool
.
- 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. Using the Clear Info function erases the stored
Freeze Frame and Failure Records from the PCM.
- Record the Freeze Frame and Failure Records.
- Clear the DTC.
- Drive the vehicle in D4 range, under the following condition:
Accelerate the vehicle, ensuring that the PCM commands 1st, 2nd, 3rd
and 4th gears.
Did you detect a 1-2-2-1 or 4-3-3-4 shift pattern?
| --
|
Go to Step 4
| Go to Diagnostic Aids
|
4
| Inspect for the following conditions:
| • | Shift solenoid screen assembly 374 for sediment or debris. |
| • | Shift solenoid for a damaged or missing O-ring. |
| • | 2-3 shift valve sticking, due to sediment, debris or damage. |
Refer to Unit Repair.
Was a condition found and corrected?
| --
|
Go to Step 6
|
Go to Step 5
|
5
| Replace the 2-3 shift solenoid valve.
Refer to
2-3 Shift Solenoid Valve Replacement
.
Is the replacement complete?
| --
|
Go to Step 6
| --
|
6
| Perform the following in order to verify the repair:
- Select DTC.
- Select Clear Info.
- 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. |
| • | Vehicle speed is more than 26 km/h (16 mph). |
| • | Engine torque is 54-271 N·m (40-200 ft lbs). |
| • | 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 2.9-4.0. |
| - | The TCC slip speed is 200-2700 RPM. |
| - | The output speed is 900-1600 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 1,500-2,800 RPM. |
| - | All of these conditions occur for more than 3 seconds. |
- Select Specific DTC.
- Enter DTC P0756.
Has the test run and passed?
| --
| System OK
|
Go to Step 1
|
