Circuit Description
The 2-3 Shift Solenoid Valve Assembly receives ignition voltage
from a fused circuit 1039 and the ground path is provided by the Powertrain
Control Module (PCM), depending on the solenoids commanded state. When the
PCM commands the solenoid OFF, a ground path is not provided and the filtered
line pressure to the solenoid is exhausted. When the PCM commands the solenoid
ON, a ground path is provided and the exhaust port is blocked, stopping the
exhaust of line pressure.
The PCM monitors the commanded gear and the speed ratio in order to
identify a malfunction in the 2-3 Shift Solenoid Valve Assembly.
When the PCM detects a 1-2-2-1 or a 4-3-3-4 shift pattern, 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. |
| • | The transmission range indicates D4. |
| • | The vehicle speed is greater than 26 km/h (16 mph). |
| • | 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 (stuck on) must occur twice. |
| • | Fail case 1 and 3 or fail case 2 and 3 (stuck off) must occur
twice. |
Failure Criteria
Case 1
| • | The PCM commands first gear for more than 1.5 seconds. |
| • | The TCC slip speed is -4,064 to -200 RPM. |
| • | 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). |
| • | 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 -4,064 to 0 RPM. |
| • | 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). |
| • | 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 last speed ratio
in second gear. |
| • | Throttle position is 14-55% and constant by 7%. |
| • | Engine torque is 54-271 N·m (40-200 ft lbs). |
| • | All of the above occurs for more than 2.0 seconds. |
Case 4
| • | The PCM commands fourth gear for more than 1.0 second. |
| • | The TCC slip speed is 1,600-6,000 RPM. |
| • | Output speed is 1,500-2,800. |
| • | 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 MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive trips 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 chart.
-
Verify the DTC and inspect shift solenoid 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 for reference. Using the Clear Info function will
erase the data.
- Record the DTC Freeze Frame and Failure Records, then clear the DTC.
- Inspect for the following conditions:
| • | Shift solenoid screen Assy. 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 5
|
Go to Step
4
|
4
| Replace the 2-3 Shift Solenoid Valve Assembly.
Refer to
2-3 Shift Solenoid Valve Replacement
.
Is the replacement complete?
| --
|
Go to Step
5
| --
|
5
| In order to verify your repair, perform the following procedure:
- Using the scan tool, clear DTCs.
- 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
|
