Circuit Description
The 2-3 shift solenoid (SS) valve is a normally-closed exhaust valve that, in conjunction with the 1-2 SS valve, allows 4 different shifting combinations. The 2-3 SS valve is attached to the control valve body, within the transmission.
The transmission control module (TCM) monitors the actual gear ratio, and compares the actual gear ratio with the commanded gear ratio. DTC P0757 sets under two conditions:
| • | A stuck ON 2-3 SS valve |
| • | A stuck ON 2-3 shift valve |
If the TCM detects a 1-2-2-1-1 shift pattern, then DTC P0757 sets. DTC P0757 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0757 2-3 Shift Solenoid (SS) Valve Performance - No Third, Fourth or Fifth Gear
Conditions for Running the DTC
| • | The ignition voltage is between 8-18 volts. |
| • | The engine speed is between 450 and 6,800 RPM for at least 5 seconds. |
| • | No TP sensor DTC P0120. |
| • | No IMS DTCs P1815, P1820, P1822, P1823, P1825 or P1826. |
| • | Engine torque default values are not being used. |
| • | No shift solenoid electrical DTCs P0973, P0974, P0976, P0977, P0979, or P0980. |
| • | No TCC stuck ON DTC P0742. |
| • | No ISS DTC P0716 or P0717. |
| • | No OSS DTC P0722 or P0723. |
| • | No shift solenoid electrical DTCs P0973, P0974, P0976, P0977, P0979, or P0980. |
| • | The IMS range is not PARK, NEUTRAL or REVERSE. |
| • | The TFT is 20-130°C (68-266°F). |
| • | The input shaft speed is 200-6,800 RPM. |
| • | The output shaft speed is greater than 100 RPM. |
Conditions for Setting the DTC
Both of the following conditions must occur once during the same trip:
| • | The TCM commands 3rd gear when the output shaft speed is 200 RPM or greater, the engine torque is greater than 20-450 N·m (15-334 lb ft), and the resulting gear ratio is 2.16:1-2.27:1, and the TP angle is more than 10 percent for 2 seconds. |
| • | When the engine torque is between 12-450 N·m (9-334 lb ft) The TCM commands 4th or 5th gear, the resulting gear ratio is 3.33:1-3.50:1, and the TP angle is greater than 10 percent for 2 seconds. |
Action Taken When the DTC Sets
| • | The TCM requests the 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 and 5th gears. |
| • | The TCM inhibits TCC. |
| • | The TCM inhibits autograde braking. |
| • | 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 sixth 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 numbers below refer to the step numbers on the diagnostic table.
-
This step verifies a 1-2-2-1-1 shift pattern.
-
This step tests for a mechanical or hydraulic condition causing the 2-3 SS valve to be stuck ON, or the circuit to be released.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||
2 | Perform the Transmission Fluid Checking Procedure. Refer to Transmission Fluid Check . Did you perform the Transmission Fluid Checking Procedure? | -- | Go to Step 3 | Go to Transmission Fluid Check | ||||||||
Important:
Are the commanded gear and gear ratio within the specified range? | 3rd 2.16:1-2.27:1 4th/5th 3.33:1-3.50:1 | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections | |||||||||
Refer to 2-3 Shift Solenoid Valve Replacement . Did you complete the repair? | -- | Go to Step 5 | -- | |||||||||
5 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 6 | Go to Step 2 | ||||||||
6 | 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 |
