DTC P1750 3.5L
Circuit Description
The 1-2 shift valve is used to direct fluid for shifting between 1st and 2nd gears. In 1st gear, the 1-2 shift solenoid (SS) valve is commanded ON causing 1-2, 3-4 signal fluid pressure to overcome the 1-2 shift valve spring force, moving the 1-2 shift valve into a position that routes D4 fluid into the Low/1st fluid passage. In 2nd gear, the 1-2 SS valve is commanded OFF allowing 1-2, 3-4 signal fluid to be exhausted and the 1-2 shift valve spring force then moves the 1-2 shift valve into a position that routes D4 fluid into the 2nd fluid passage.
If the powertrain control module (PCM) detects a 1st gear ratio when 2nd gear is commanded indicating a stuck 1-2 shift valve, then DTC P1750 sets. DTC P1750 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1750 1-2 Shift Valve Performance
Conditions for Running the DTC
| • | No MAF DTCs P0101, P0102, or P0103. |
| • | No MAP DTCs P0107 or P0108. |
| • | No VSS DTC P0502 or P0503. |
| • | No ISS sensor DTC P0716 or P0717. |
| • | The engine is running for 5 seconds or more and not in fuel cut off. |
| • | The vehicle speed is greater than 16 km/h (10 mph). |
| • | The TP indicated angle is greater than 8 percent. |
| • | The transmission fluid temperature (TFT) is 20°C (68°F) or more. |
| • | The engine torque is greater than 50 N·m (37 lb ft). |
| • | The time since the last gear change is 0.2 seconds. |
Conditions for Setting the DTC
The PCM commands 2nd gear for 1 second or more and gear ratio is 2.87:1-3.13:1 for 5 seconds.
Action Taken When the DTC Sets
| • | The PCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM commands maximum line pressure |
| • | The PCM forces the TCC OFF. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM inhibits 3-2 downshifts when the vehicle speed is greater than 52 km/h (32 mph). |
| • | The PCM freezes transmission adaptive functions. |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records. |
| • | The PCM stores DTC P1750 in PCM history. |
Conditions for Clearing the DTC
| • | A scan tool can clear the DTC. |
| • | 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 ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
If DTC P1750 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist:
| • | Fluid contamination |
| • | Plugged fluid circuits |
| • | Restricted fluid circuits |
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||
2 | Did you perform the Transmission Fluid Checking Procedure? | -- | Go to Step 3 | Go to Transmission Fluid Check | ||||||||
3 |
Important: Before clearing the DTCs, use the scan tool in order to record the Failure Records for reference. Using the Clear DTC Information function will erase the Failure Records from the PCM. Is DTC P0752 also set? | -- | Go to DTC P0752 (3.5L) | Go to Step 4 | ||||||||
4 |
Did the gear ratios indicate a 1-1-3-4 shift pattern? | 1st: 2.87:1 to 3.13:1 2nd: 1.54:1 to 1.71:1 3rd: 0.91:1 to 1.07:1 4th: 0.61:1 to 0.71:1 | Go to Step 5 | Go to Diagnostic Aids | ||||||||
5 | Inspect the 1-2 shift valve/hydraulic circuit for a stuck or binding 1-2 shift valve. Refer to the following procedures:
Did you find and correct the condition? | -- | Go to Step 6 | -- | ||||||||
6 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | 2nd: 1.54:1 to 1.71:1 | Go to Step 7 | Go to Step 2 | ||||||||
7 | With a 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 |
