Circuit Description
The automatic transmission (AT) clutch pressure control (PC) solenoid valve 1 is attached to the exterior of the transmission case. Upon receiving a linear current signal from the powertrain control module (PCM), it converts the modulated pressure to a regulated control pressure and supplies it for use in the pressure regulation, using the spring P at the clutch PC valve. The linear current from the PCM is output to the clutch of an appropriate gear position as determined by the shift schedule, so that a clutch control pressure appropriate for the driving condition is supplied. When the linear current from the PCM is on the high current side, the AT clutch PC solenoid valve 1 operates and the pressure regulated control pressure shifts to the high pressure side, ON. When the linear current is on the low voltage side, the AT clutch PC solenoid valve 1 stops operating and the pressure regulated control pressure shifts to the low pressure side, OFF. The PCM monitors mainshaft to output shaft speed ratio in the gear positions determined by the shift schedule.
When the PCM detects an incorrect ratio for the commanded gear, DTC P0746 sets. DTC P0746 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0746 Clutch Pressure Control (PC) Solenoid 1 - Stuck Off
Conditions for Running the DTC
| • | No TP DTCs P0122, P0123, P0222, or P0223. |
| • | No VSS DTCs P0501, P0502, or P0503. |
| • | No AT ISS DTCs P0716, P0717, or P0718. |
| • | No Clutch PC Performance DTC P0747. |
| • | No SS Valve Performance DTCs P0751, P0752, P0756, P0761, P0757, or P0762. |
| • | No Incorrect Shift Pattern DTC P0780. |
| • | No Clutch PC Solenoid Electrical DTCs P0962 or P0963. |
| • | No Clutch PC Solenoid 2 DTCs P0966 or P0967. |
| • | No SS 1 DTCs P0973 or P0974. |
| • | No SS 2 DTCs P0976 or P0977. |
| • | No SS 3 DTCs P0979 or P0980. |
| • | No TAC DTCs P2101, P2108, P2111, P2112, or P2553. |
| • | No APP DTC P2122, P2123, P2127, P2128, P2135, or P2138. |
| • | No Minimum Idle Position DTC P2176. |
| • | No TCC PC Solenoid DTCs P2763 or P2764. |
| • | No TCC Enable Solenoid DTCs P2769 or P2770. |
| • | No TAC Communication DTC U0107. |
| • | The system voltage is 11 volts or greater. |
| • | The engine coolant temperature (ECT) is 10°C (50°F) or greater. |
| • | The transmission fluid temperature (TFT) is -20°C (-4°F) or greater. |
| • | Start the engine and drive so that the transmission shifts from 1st to 5th gear. |
Conditions for Setting the DTC
Case 1
The gear remains in 1st gear in response to a 1-2 upshift command.
Case 2
The engine speed rises abnormally in all upshift except 1-2 upshift operations.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
| • | The PCM limits the transmission shift to 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 and Failure Records. |
| • | The PCM stores DTC P0746 in PCM history. |
Conditions for Clearing the MIL/DTC
| • | 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. |
| • | The PCM limits the transmission to 4th gear. |
| • | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an 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
| • | Inspect for an AT clutch PC solenoid valve stuck OFF. |
| • | Inspect for a stuck clutch PC solenoid valve 1. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step inspects the transmission fluid to ensure that it is at the proper level.
-
During the clutch PC solenoid valve 1 operation, listen for an audible click. Command the ON and the OFF states. Repeat the commands as necessary.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||||
Did you perform the Transmission Fluid Checking Procedure? | Go to Step 3 | Go to Transmission Fluid Check | |||||||
3 |
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. Does the DTC reset? | Go to Step 4 | Go to Diagnostic Aids | ||||||
Does the Clutch PC Solenoid 1 Functional Test Status display complete? | Go to Step 5 | Go to Step 6 | |||||||
5 |
Did you complete the repair? | Go to Step 7 | -- | ||||||
6 | Replace the clutch PC solenoid valve 1. Refer to A/B Clutch Pressure Control Solenoid Assembly Replacement . Did you complete the replacement? | Go to Step 7 | -- | ||||||
7 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | Go to Step 8 | Go to Step 2 | ||||||
8 | 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 |
