This diagnostic procedure supports DTC P0757 2-3 Shift Solenoid (SS) Valve Performance-No Third or Fourth Gear.
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.
Refer to 2 Wiring Diagram and Connector Chart to aid in diagnosis.
• | No DTCs P0120, P0722, P0723, P0742, P0974, P0976, P0977 or P1815. |
• | The engine torque is 108-882 N·m. |
• | The engine run time is greater than 5 seconds. |
• | The transmission fluid temperature is 20-130°C. |
• | The throttle position is greater than 10 percent. |
• | The output shaft speed is greater than 150 RPM. |
The TCM commands 3rd gear and the resulting gear ratio is a 1.44:1-1.53:1, 1st gear, for 2.25 seconds.
• | The TCM requests the ECM to illuminate the check powertrain icon 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. |
• | The ECM turns off the check powertrain icon after the fourth consecutive drive trip in which the TCM does not send a check powertrain icon illumination request. |
• | Tech 2 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. |
• | If you clear DTC P0757, and then cannot reset DTC P0757, the following conditions may exist: |
- | Fluid contamination, |
- | Blocked fluid circuits, or |
- | Restricted fluid circuits. |
• | Refer to Shift Solenoid Valve State and Gear Ratio. |
The following numbers refer to the step numbers in the diagnostic table:
2 This step tests the TCM commanded all shifts, all shift solenoid valves responded correctly, and if all the shifts did not occur.
3 Checks the mechanical components that cause the DTC and their state.
Step | Action | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|
1 | Has the Diagnostic System Check been performed? | Go to Step 2 | |||||||
2 |
Important: Before clearing the DTC, use the Tech 2 Freeze Frame/Failure Record in order to record the transmission parameters at the time the DTC set. Using Tech 2 to clear the DTC(s) erases the Freeze Frame/Failure Record records from the TCM Transmission / Automatic Transmission / Diagnostic Trouble Codes / Freeze Frame. Diagnostic Trouble Codes / Clear Engine and Transmission DTCs.
Did you detect a 1-2-2-1 shift pattern? | Go to Step 3 | Refer to Diagnostic Aids within this Section | ||||||
3 | Inspect the shift solenoid/hydraulic circuit for the following conditions:
| Go to Step 4 | -- | ||||||
4 | Perform the following procedure in order to verify the repair:
Has DTC P0757 set? | Go to Step 2 | Go to Step 5 | ||||||
5 | On Tech 2 select: Diagnostic Trouble Codes / Read DTC Information. Does Tech 2 display any DTCs you have not diagnosed? | System OK | |||||||
When all diagnosis and repairs are completed, check the system for correct operation. |