DTC P0776: Pressure Control Solenoid "B" Performance/Stuck Off: Notes

WARNING: This page is about a different car, the 2020 Subaru Impreza. 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:

Engine speed increases abruptly, and cannot accelerate.
Excessive slippage is felt.

Wiring diagram:

CVT control system Ref. to WIRING SYSTEM (IMPREZA MODEL)>CVT CONTROL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

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) (IMPREZA MODEL)>BASIC DIAGNOSTIC PROCEDURE .

Courtesy of SUBARU OF AMERICA, INC.

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

Besides DTC P0776, is any of the DTC P0717, P0966, P0967 or P2747 displayed?

Yes : Perform the diagnosis according to DTCs other than P0776. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

No : Go to 2.
CHECK F & R SOLENOID (ACTIVE TEST) .
1. Turn the ignition switch to ON.
2. Using the Subaru Select Monitor, perform the active test for F & R solenoid. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>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 F & R SOLENOID .
1. Turn the ignition switch to OFF.
2. Disconnect the TCM connector.
3. Measure the resistance between TCM connector and transmission body.
  Connector & terminal
  
  (T10) No. 16 - Transmission body:
Is the resistance approximately 3.5 - 7.1 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 the TCM connector.
2. Check the amount of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>CVTF>ADJUSTMENT .
Is the check result OK?

Yes : Go to 6.

No : Adjust the amount of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>CVTF>ADJUSTMENT .
CHECK TRANSMISSION FLUID .
Check the condition of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>CVTF>CONDITION CHECK .

Is the check result OK?

Yes : Go to 7.

No : Check according to the "Corrective action" of ATF (CVTF) "CONDITION CHECK". Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>CVTF>CONDITION CHECK .
CHECK INPUT SIGNAL FOR TCM .
1. Lift up the vehicle.
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 shift the select lever to "D" range.
5. Shift the select lever to "P" range.
6. Stabilize the engine speed at idle.
7. Using the Subaru Select Monitor, read data of [Actual Secondary Pressure] in the [Data Monitor] of [Transmission]. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DATA MONITOR .
Is [Actual Secondary Pressure] 0.5 - 1.5 [MPa]?

Yes : Go to 8.

No : Perform the diagnosis according to DTC P0841. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC P0841 TRANSMISSION FLUID PRESSURE SENSOR/SWITCH "A" CIRCUIT RANGE/PERFORMANCE .
STALL TEST .
Perform the stall test. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>STALL TEST .

Is the result of the stall test OK?

Yes : Go to 9.

No : Replace the transmission assembly if the stall speed is higher than the standard value of the stall test. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>AUTOMATIC TRANSMISSION ASSEMBLY .
DRIVING CHECK BY INSPECTION MODE .
1. Using the Subaru Select Monitor, perform the clear memory of [Transmission]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
2. Execute the inspection mode. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>INSPECTION MODE .
Does the AT OIL TEMP light blink and is DTC P0776 displayed?

Yes : Replace the transmission assembly. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>AUTOMATIC TRANSMISSION ASSEMBLY .

No : Current condition is normal. It is possible that temporary poor contact occurs.