Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p0776 pressure control solenoid "b" performance/stuck off

Subaru Legacy BN/BS (2015-2019) Service Manual / Continuously variable transmission (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p0776 pressure control solenoid "b" performance/stuck off

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

TROUBLE SYMPTOM:

• Engine speed increases abruptly, and can not accelerate.

• Excessive slippage is felt.

1. ENGINE TYPE FB

WIRING DIAGRAM:

CVT control system CVT Control System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK DTC. Read the DTC using Subaru Select Monitor.	Besides DTC P0776, is any of the DTC P0717, P0966, P0967 or P2747 displayed-	Perform the diagnosis according to DTCs other than P0776.	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF
2.CHECK F&R SOLENOID (ACTIVE TEST). 1) Turn the ignition switch to ON. 2) Using the Subaru Select Monitor, perform forced operation of the F&R solenoid. Active Test	Does the indication of 0 > 500 mA appear repeatedly during forced operation, and does operating sound emit during indicating 500 mA-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF
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 approx. 4 — 6 -- (when cold)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF
4.CHECK HARNESS. Check the harness for continuity.	Is the harness normal- (Is it free from defects such as open circuit, power supply-output short or GND-output short circuit, or poor contact-)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Repair the harness.
5.CHECK TRANSMISSION FLUID. 1) Connect the TCM connector. 2) Check the amount of ATF. CVTF > ADJUSTMENT	Is the ATF amount correct-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Adjust the amount of ATF. CVTF > ADJUSTMENT
6.CHECK TRANSMISSION FLUID. Check the condition of ATF. CVTF > CONDITION CHECK	Is the ATF OK-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Check according to the “Corrective action” of ATF (CVTF) “CONDITION CHECK”. CVTF > CONDITION CHECK
7.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) Read the data of «Actual secondary pressure» using Subaru Select Monitor.	Is the «Actual secondary pressure» 0.5 — 1.5 MPa-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Perform the diagnosis according to DTC P0841. Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0841 TRANSMISSION FLUID PRESSURE SENSOR/SWITCH “A” CIRCUIT RANGE/PERFORMANCE
8.STALL TEST. Perform the stall test. Stall Test	Is the stall test normal-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Replace the transmission assembly if the stall speed is higher than the standard value of the stall test. Automatic Transmission Assembly
9.DRIVING CHECK BY INSPECTION MODE. 1) Turn the ignition switch to OFF. 2) Perform a drive check based on the “Inspection Mode”. Inspection Mode	Does the AT OIL TEMP light blink and is DTC P0776 displayed-	Replace the transmission assembly. Automatic Transmission Assembly	Current condition is normal. It is possible that temporary poor contact occurs.

2. ENGINE TYPE EZ

WIRING DIAGRAM:

CVT control system CVT Control System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK DTC. Read the DTC using Subaru Select Monitor.	Besides DTC P0776, is any of the DTCs P0720, P0966, P0967, P1706 and P2751 displayed-	Perform the diagnosis according to DTCs other than P0776.	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF
2.CHECK F&R SOLENOID (ACTIVE TEST). 1) Turn the ignition switch to ON. 2) Using the Subaru Select Monitor, perform forced operation of the F&R solenoid. Active Test	Does the indication of 0 > 500 mA appear repeatedly during forced operation, and does operating sound emit during indicating 500 mA-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF
3.CHECK F&R 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 (T4) No. 9 — Transmission body:	Is the resistance approx. 4 — 6 -- (when cold)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF
4.CHECK HARNESS. Check the harness for continuity.	Is the harness normal- (Is it free from defects such as open circuit, power supply-output short or GND-output short circuit, or poor contact-)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Repair the harness.
5.CHECK TRANSMISSION FLUID. 1) Connect the transmission connector. 2) Check the amount of ATF. CVTF > ADJUSTMENT	Is the ATF amount correct-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Adjust the amount of ATF. CVTF > ADJUSTMENT
6.CHECK TRANSMISSION FLUID. Check the condition of ATF. CVTF > CONDITION CHECK	Is the ATF OK-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Check according to the “Corrective action” of ATF (CVTF) “CONDITION CHECK”. CVTF > CONDITION CHECK
7.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) Read the data of «Actual secondary pressure» using Subaru Select Monitor.	Is the «Actual secondary pressure» 0.5 — 1.5 MPa-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Perform the diagnosis according to DTC P0841. Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0841 TRANSMISSION FLUID PRESSURE SENSOR/SWITCH “A” CIRCUIT RANGE/PERFORMANCE
8.STALL TEST. Perform the stall test. Stall Test	Is the stall test normal-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0776 PRESSURE CONTROL SOLENOID "B" PERFORMANCE/STUCK OFF	Replace the transmission assembly if the stall speed is higher than the standard value of the stall test. Automatic Transmission Assembly
9.DRIVING CHECK BY INSPECTION MODE. 1) Turn the ignition switch to OFF. 2) Perform a drive check based on the “Inspection Mode”. Inspection Mode	Does the AT OIL TEMP light blink and is DTC P0776 displayed-	Replace the transmission assembly. Automatic Transmission Assembly	Current condition is normal. It is possible that temporary poor contact occurs.

3. OUTLINE OF DIAGNOSIS (ENGINE TYPE FB)

• Detect the malfunction of transmission forward/reverse clutch pressure solenoid and hydraulic circuit characteristics (stuck to low pressure side).

• Judge as NG if the value calculated by “turbine speed − primary pulley speed” becomes the predetermined value or more, even though the forward/reverse clutch is engaged.

4. EXECUTION CONDITION (ENGINE TYPE FB)

Secondary Parameters	Execution condition
Diagnosis 1
12 V battery system voltage	≥ 10 V
Transmission range	Drive
Measured turbine shaft speed	≥ 100 rpm
Measured primary pulley shaft speed	≥ 100 rpm
Commanded forward & reverse clutch pressure control solenoid current	< 0.9 A
Engine speed	≥ 500 rpm
Diagnosis 2
12 V battery system voltage	≥ 10 V
Transmission range	Drive
Measured primary pulley shaft speed	< 100 rpm
Commanded forward & reverse clutch pressure control solenoid current	< 0.9 A
Accelerator pedal position (from ECM)	> 6%
Engine speed	≥ 500 rpm

5. DIAGNOSTIC METHOD (ENGINE TYPE FB)

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Judgment Value

Malfunction Criteria	Threshold Value
Diagnosis 1
\|Measured turbine shaft speed − Measured primary pulley shaft speed\|	> Table 1 rpm
Diagnosis 2
Measured turbine shaft speed	> 2000 rpm

Table 1

Vehicle speed (MPH)	0	13	25	38	50	63	75
\|Measured turbine shaft speed − Measured primary pulley shaft speed\|(rpm)	150	100	100	100	100	100	100

Vehicle speed (MPH)	88	100	113	125	138	150	159
\|Measured turbine shaft speed − Measured primary pulley shaft speed\|(rpm)	100	100	100	100	100	100	100

Time Needed for Diagnosis: 5 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

6. OUTLINE OF DIAGNOSIS (ENGINE TYPE EZ)

• Detect the malfunction of transmission forward/reverse clutch pressure solenoid and hydraulic circuit characteristics (stuck to low pressure side).

• Judge as NG if the value calculated by “output speed − secondary pulley speed” becomes the predetermined value or more, even though the forward/reverse clutch is engaged.

7. EXECUTION CONDITION (ENGINE TYPE EZ)

Secondary Parameters	Execution condition
Diagnosis 1
12 V battery system voltage	≥ 10 V
Transmission range	Drive
Measured secondary pulley shaft speed	≥ 100 rpm
Measured front output shaft speed	≥ 100 rpm
Commanded forward & reverse clutch pressure control solenoid current	< 0.9 A
Engine speed	≥ 500 rpm
Diagnosis 2
12 V battery system voltage	≥ 10 V
Transmission range	Drive
Measured front output shaft speed	< 100 rpm
Commanded forward & reverse clutch pressure control solenoid current	< 0.9 A
Accelerator pedal position (from ECM)	> 6%
Engine speed	≥ 500 rpm

8. DIAGNOSTIC METHOD (ENGINE TYPE EZ)

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Judgment Value

Malfunction Criteria	Threshold Value
Diagnosis 1
\|Measured front output shaft speed − Measured secondary pulley shaft speed /1.322\|	> Table 2 rpm
Diagnosis 2
Measured secondary pulley shaft speed	> 600 rpm

Table 2

Vehicle speed (MPH)	0	13	25	38	50	63	75
\|Measured front output shaft speed − Measured secondary pulley shaft speed\|(rpm)	150	100	100	100	100	100	100

Vehicle speed (MPH)	88	100	113	125	138	150	159
\|Measured front output shaft speed − Measured secondary pulley shaft speed\|(rpm)	100	100	100	100	100	100	100

Time Needed for Diagnosis: 5 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

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