Circuit Description
The 2-3 Shift Solenoid receives ignition voltage from circuit 1339
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, energizing the solenoid which blocks the exhaust port. This
allows line pressure to the fluid passage.
The PCM monitors the commanded gear and the speed ratio in order to
identify a malfunction in the 2-3 Shift Solenoid Valve.
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 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 either of the following, Stuck ON or
Stuck OFF, fail conditions must occur:
| • | Stuck On Fail case 3 and 4 must occur twice. |
| • | Stuck Off Fail case 1 and 3 or fail case 2 and 3 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 800-1700 RPM. |
| • | The speed ratio is 0.7-2.5. |
| • | 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 -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%. |
| • | All of the above occurs for more than 2.0 seconds. |
Case 3
| • | The PCM commands third gear for 2.5-7.5 seconds. |
| • | Throttle position is 14-45% and constant by 7%. |
| • | The TCC slip speed is 600 RPM more than the last slip speed
in second gear. |
| • | The speed ratio is not 0.4 less than the 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 greater than 10%. |
| • | Engine torque is 0 to 68 N·m (0 to 50 ft lbs). |
| • | The TCC slip speed is 1,600-6,000 RPM. |
| • | Output speed is 1,500-2,800. |
| • | The speed ratio is 2-4. |
| • | 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 table.
-
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
in Engine Controls
|
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 stored Freeze Frame
and Failure Records from the PCM.
- 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. |
| • | 2-3 shift solenoid for a damaged or missing O-ring. |
| • | 2-3 shift valve sticking, due to sediment, debris or damage. |
Refer to
Transmission Overhaul
in the 4T60-E Section of the Transmission Unit Repair Manual.
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 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 DTC information.
- Operate the vehicle under the following conditions:
| • | The engine speed is more than 500 RPM for 5 seconds. |
| • | The vehicle is not in fuel shut off. |
| • | The transmission fluid temperature is 20-130°C (68-268°F). |
| • | The 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 3-4.0. |
| - | The TCC slip speed is 200-2,700 RPM. |
| - | The output speed is 800-1,700 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
|
