Circuit Description
The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the
2-3 shift valves. The 2-3 SS valve is a normally-open exhaust valve
that is used with the 1-2 SS valve in order to allow 4 different
shifting combinations.
When the powertrain control module (PCM) detects a 1-2-2-1 shift pattern, then
DTC P0757 sets. DTC P0757 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0757 2-3 Shift Solenoid Valve Performance - No Third or Fourth Gear
Conditions for Running the DTC
| • | No TP sensor DTCs P0122 or P0123. |
| • | No VSS DTCs P0502 or P0503. |
| • | No TCC solenoid valve DTC P0740. |
| • | No TCC stuck ON DTC P0742. |
| • | No 1-2 SS valve DTC P0753. |
| • | No 2-3 SS valve DTC P0758. |
| • | No 3-2 SS valve DTC P0785. |
| • | No TFP manual valve position switch DTC P1810. |
| • | No TCC PWM solenoid valve DTC P2761. |
| • | The engine speed is greater than 450 RPM for 5 seconds. |
| • | The engine is not in fuel cut-off. |
| • | The TP angle is greater than 10 percent. |
| • | The transmission fluid temperature is 20-130°C (68-266°F). |
| • | The system voltage is 10-18 volts. |
| • | The engine torque is 0-542 N·m (0-400 lb ft). |
| • | The transmission output speed is 150 RPM or greater. |
Conditions for Setting the DTC
DTC P0757 sets if both of the following conditions occur:
Condition 1
| • | The PCM commands third gear for 1 second. |
| • | The estimated gear ratio is 1.6-1.8. |
| • | The engine torque is 68-542 N·m (50-400 lb ft). |
| • | All conditions are met for 2 seconds. |
Condition 2
| • | The PCM commands fourth gear for 1 second. |
| • | The estimated gear ratio is 1.8-3.3. |
| • | The engine torque is 0-542 N·m (0-400 lb ft). |
| • | All conditions are met for 2 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL). |
| • | The PCM commands third gear only. |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM inhibits fourth gear in hot mode. |
| • | The PCM freezes shift adapts from being updated. |
| • | The PCM records the operating conditions when the Conditions for Setting
the DTC are met. The PCM stores this information as Freeze Frame and Failure Records. |
| • | The PCM stores DTC P0757 in PCM history. |
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 can clear the MIL/DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes
40 warm-up cycles without an emission-related
diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the ignition switch
is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | Verify that the transmission meets the specifications in the
Shift Speed
table. |
| • | Other internal transmission failures may cause more than one shift to
occur. |
Test Description
The number below refers to the step number on the diagnostic table.
-
This step tests that the PCM commanded all shifts,
that all shift solenoid valves responded correctly, but that all the shifts did not
occur.
DTC P0757
Step
| Action
| Values
| Yes
| No
|
1
| Did you perform the Diagnostic System Check - Vehicle?
| --
| Go to
Step 2
| Go to
Diagnostic System Check - Vehicle
in
Vehicle DTC Information
|
2
|
- Install a scan tool.
- Turn ON the ignition, with the engine OFF.
Important: Before clearing the DTC, use the scan tool
in order to record the Freeze Frame and Failure Records. Using the Clear Info function
erases the Freeze Frame and Failure Records from the PCM.
- Record the DTC Freeze Frame and Failure Records.
- Clear the DTC.
- Drive the vehicle in D4 range under the following conditions:
Accelerate the vehicle, ensuring that the PCM commands 1st, 2nd, 3rd and 4th gears.
Did you detect a 1-2-2-1 shift pattern?
| --
| Go to
Step 3
| Go to Diagnostic Aids
|
3
| Inspect the shift solenoid/hydraulic circuit for the following conditions:
| • | An internal malfunction |
| • | Damaged seals on the shift solenoid valve |
Did you find and correct the condition?
| --
| Go to
Step 4
| --
|
4
| Perform the following procedure in order to verify the repair:
- Select DTC.
- Select Clear Info.
- Drive the vehicle in D4 range under the following conditions, only if
traffic and road conditions permit:
Hold the throttle at 15% and accelerate
to 80 km/h (55 mph).
- Select Specific DTC.
- Enter DTC P0757.
Has the test run and passed?
| --
| Go to
Step 5
| Go to
Step 2
|
5
| With the scan tool, observe the stored information, capture info, and DTC Info.
Does the scan tool display any DTCs that you have not diagnosed?
| --
| Go to
Diagnostic Trouble Code (DTC) List - Vehicle
in Vehicle DTC Information
| System OK
|
