Circuit Description
The 2-3 shift solenoid (SS) valve controls fluid flow acting on the 2-3 shift valves. The 2-3 SS valve is a normally open exhaust valve used with the 1-2 SS valve in order to allow for four different shift combinations.
If the powertrain control module (PCM) detects a non third gear ratio while third gear is commanded, then DTC P0757 sets. DTC P0757 is a type C DTC. For California emissions vehicles and vehicles under 8,600 GVW, DTC P0757 is a type A DTC.
Conditions for Running the DTC
| • | No MAF sensor DTCs P0101, P0102 or P0103. |
| • | No MAP sensor DTCs P0106, P0107, or P0108. |
| • | No TP sensor DTCs P0120 or P0220. |
| • | No VSS DTCs P0502 or P0503. |
| • | No ISS DTCs P0716 or P0717. |
| • | No shift solenoid electrical DTCs P0753 or P0758. |
| • | No transmission component slipping DTC P0894. |
| • | No TFP manual valve position switch DTC P1810. |
| • | No TCC Stuck On DTC P0742. |
| • | No TCC PWM electrical DTC P2761. |
| • | Transmission ISS is greater than 7 RPM. |
| • | The engine is running for greater than 7 seconds. |
| • | Not in 4WD low. |
| • | Transmission OSS is greater than 7 RPM. |
| • | The system voltage is 10-18 volts. |
| • | The throttle angle is greater than 10 percent. |
| • | The transmission fluid temperature (TFT) is greater than 20°C (68°F) and less than 130°C (266°F). |
| • | The engine torque must be 108-542 N·m (80-400 lb ft). |
Conditions for Setting the DTC
| • | The commanded gear equals 3rd and the ratio is 2nd for greater than 2.25 seconds. |
| • | All conditions are met for 7 occurrences. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) for California emissions vehicles. |
| • | The PCM commands a soft landing to 2nd gear. |
| • | The PCM commands maximum line pressure. |
| • | The PCM freezes transmission adaptive functions. |
| • | The PCM inhibits 4th gear. |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame, California only, and Failure Records, California and Federal. |
| • | The PCM stores DTC P0757 in PCM history. |
Conditions for Clearing the MIL/DTC
| • | For California emissions, 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. |
| • | For California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring. |
| • | For Federal emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and 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. Refer to Shift Speed . |
| • | Other internal transmission failures may cause incorrect gear ratios to occur in 3rd gear. |
| • | The customer may have concern of an engine over-rev condition or neutral condition in 4th gear. Refer to Shift Solenoid Valve State and Gear Ratio . |
| • | DTC P0757 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 4.8L, 5.3L, and 6.0L | ||||||||||
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. Did you detect a 1-2-2-1 shift pattern? | -- | Go to Step 3 | Go to Intermittent Conditions in Engine Controls - 4.8L, 5.3L, and 6.0L | |||||||||||
3 |
Refer to Control Valve Body Cleaning and Inspection in Transmission Unit Repair Manual. Did you find and correct the condition? | -- | Go to Step 4 | -- | ||||||||||
4 | Perform the following procedure in order to verify the repair:
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 in Engine Controls - 4.8L, 5.3L, and 6.0L | System OK |
