DTC P0746: Pressure Control Solenoid "A" Performance/Stuck Off: Notes

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.

1. -

DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

Trouble symptom:

Acceleration is poor during standing start.
Shift control malfunction

Wiring diagram:

CVT control system Ref. to WIRING SYSTEM>CVT CONTROL SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Before performing diagnosis, record the freeze frame data.
Use the check board when measuring the TCM terminal voltage and resistance.
After servicing or replacing faulty parts, perform the last step of the basic diagnostic procedure. Ref. to TRANSMISSION (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE

CHECK DTC .
Read the DTC of [Transmission] using the Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)

Besides DTC P0746 and P0867, is DTC P0842, P0843, P0962, or P0963 displayed?

Yes : Perform the diagnosis according to DTCs other than P0746 and P0867. Ref. to TRANSMISSION (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST

No : Go to 2.
CHECK LINE PRESSURE SOLENOID (ACTIVE TEST) .
1. Turn the ignition switch to ON.
2. Using the Subaru Select Monitor, perform the active test for line pressure solenoid. Ref. to TRANSMISSION (DIAGNOSTICS)>ACTIVE TEST
Does the indication of 0 → 500 mA appear repeatedly during the active test, and does operating sound emit during indicating 500 mA?

Yes : Go to 5.

No : Go to 3.
CHECK LINE PRESSURE SOLENOID .
1. Turn the ignition switch to OFF.
2. Disconnect the transmission connector.
3. Measure the resistance between transmission connector and transmission body.
  Connector & terminal
  
  (T1) No. 11 - Transmission body:
Is the resistance approximately 3.3 - 7.3 Ω? (When cold)

Yes : Go to 7.

No : Go to 4.
CHECK HARNESS .
Check the transmission harness. (Open circuit, short circuit to power supply, short circuit to ground, and poor contact)

Is the check result OK?

Yes : Go to 7.

No : Repair the harness.
CHECK TRANSMISSION FLUID .
1. Connect all connectors.
2. Check the amount of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>CVTF>INSPECTION
Is the check result OK?

Yes : Go to 6.

No : Adjust the amount of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>CVTF>INSPECTION Go to 6.
CHECK TRANSMISSION FLUID .
Check the condition of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>CVTF>INSPECTION

Is the check result OK?

Yes : Return ATF. Go to 7.

No : Follow the "Corrective action" of ATF (CVTF) "CONDITION CHECK". Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>CVTF>REPLACEMENT Go to 7.
CHECK INPUT SIGNAL FOR TCM .
1. Using the Subaru Select Monitor, perform the clear memory of [Transmission]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY
2. Start the engine.
3. Warm up until the ATF temperature reaches to 40 - 70°C (104 - 158°F).
4. Depress the brake pedal and move the select lever to each range at an interval of 5 seconds.
  NOTE:
  Move the select lever in the following order: "P" → "R" → "N" → "D" → "N" → "R" → "P".
5. Stabilize the engine speed at idle.
6. Using the Subaru Select Monitor, read data of [Actual line press.] in the [Data Monitor] of [Transmission]. Ref. to TRANSMISSION (DIAGNOSTICS)>DATA MONITOR
Is [Actual line press.] 0.5 - 1.5 MPa?

Yes : Go to 8.

No : Replace the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>CONTROL VALVE BODY
CHECK INPUT SIGNAL FOR TCM .
1. Shift the select lever to "P" range.
2. Keep the engine speed at 3, 000 rpm.
3. Using the Subaru Select Monitor, read data of [Actual line press.] in the [Data Monitor] of [Transmission]. Ref. to TRANSMISSION (DIAGNOSTICS)>DATA MONITOR
Is [Actual line press.] 1.5 - 2.5 MPa? Is the difference between the actual oil pressure and the value measured in Step 7 0.2 MPa or more?

Yes : Go to 9.

No : Replace the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>CONTROL VALVE BODY

CHECK FREEZE FRAME DATA .

Turn the ignition switch to OFF.
Check the recorded freeze frame data for DTC P0867. Ref. to TRANSMISSION (DIAGNOSTICS)>FREEZE FRAME DATA

Apply the values of [Actual line press.] and [Lin. Sol. Actual Current] recorded in the freeze frame data onto the graph shown in the following figure, and judge if either low-voltage malfunction or high-voltage malfunction occurs.

Courtesy of SUBARU OF AMERICA, INC.

NOTE:

Symptom that the DTC P0867 illuminates can be classified into 2 patterns.

Low-voltage malfunction: detected due to insufficient oil pressure
High-voltage malfunction: detected due to excessive oil pressure

Was the detected symptom low-voltage malfunction?

Yes : Replace the transmission assembly. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSMISSION ASSEMBLY

No : Go to 10.

CHECK TCM INPUT SIGNAL (STALL TEST) .
1. Lift up the vehicle.
2. Start the engine.
3. Apply the parking brake.
4. Set the select lever to "D" range.
5. Depress the brake pedal firmly.
6. Slowly open the accelerator fully, and stabilize the engine speed.
7. Using the Subaru Select Monitor, read data of [Actual line press.] in the [Data Monitor] of [Transmission]. Ref. to TRANSMISSION (DIAGNOSTICS)>DATA MONITOR
  CAUTION:
  Do not perform a stall test for 5 seconds or more at a time.
Is the [Actual line press.] 6.0 MPa or more?

Yes : Replace the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>CONTROL VALVE BODY

No : Replace the transmission assembly. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSMISSION ASSEMBLY