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 four different shifting combinations.
When the transmission control module (TCM) 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 (SS) Valve Performance - No Third or Fourth Gear.
Conditions for Running the DTC
| • | No throttle position (TP) sensor DTC P0120. |
| • | No output shaft speed (OSS) DTCs P0722 or P0723. |
| • | No torque converter clutch (TCC) performance DTC P0742. |
| • | No shift solenoid electrical DTCs P0973, P0974, P0976, or P0977. |
| • | No IMS DTCs P1815, P1820, P1822, P1823, P1825 or P1826. |
| • | The engine torque is between 108 N·m (80 lb ft) and 882 N·m (651 lb ft). |
| • | The engine run time is greater than 5 seconds. |
| • | The transmission fluid temperature is 20-130°C (68-266°F). |
| • | The throttle position is greater than 10 percent. |
| • | The output shaft speed is greater than 150 RPM. |
Conditions for Setting the DTC
The TCM commands 3rd gear and the resulting gear ratio is a 1.44:1-1.52:1, 1st gear, for 2.25 seconds.
Action Taken When the DTC Sets
| • | The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM inhibits 4th gear. |
| • | At the time of the first failure, the TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record. |
| • | At the time of the second failure, the ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame. |
| • | The TCM stores DTC P0757 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the DTC
| • | The ECM turns OFF the MIL after the 4th consecutive drive trip in which the TCM does not send a MIL illumination request. |
| • | A scan tool can clear the DTC. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring. |
| • | The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM. |
Diagnostic Aids
| • | If you clear DTC P0757, and then cannot reset DTC P0757, the following conditions may exist: |
| - | Fluid contamination. |
| - | Plugged fluid circuits. |
| - | Restricted fluid circuits. |
| • | Refer to Shift Solenoid Valve State and Gear Ratio . |
Test Description
The number below refers to the step number on the diagnostic table.
-
This step tests that the TCM commanded all shifts, that all shift solenoid valves responded correctly, but that all the shifts did not occur.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||
2 |
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 TCM. Accelerate the vehicle, ensuring that the TCM 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:
Did you find and correct the condition? | -- | Go to Step 4 | -- | ||||
4 | Perform the following procedure in order to verify the repair:
Hold the throttle at 15 percent and accelerate to 80 km/h (55 mph). 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? | -- | System OK |
