CONTINUOUSLY VARIABLE TRANSMISSION (DIAGNOSTICS) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)
DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF
DTC detecting condition:
Detected when two consecutive driving cycles with fault occur.
Trouble symptom:
• Shift control malfunction
• Engine speed increases abruptly.
Wiring diagram:
CVT control system CVT Control System">
STEP | CHECK | YES | NO |
1.CHECK DTC.
Read the DTC using Subaru Select Monitor.
Besides DTC P0751, is any of the DTCs P0973, P0974, P0976, P0977, P2747 and P2751 displayed?
Perform the diagnosis according to DTCs other than P0751.
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 2.
2.CHECK PRIMARY UP SOLENOID (ACTIVE TEST).
1) Turn the ignition switch to ON.
2) Using the Subaru Select Monitor, perform forced operation of the primary UP solenoid. Active Test">
Does the indication of 0 > 50% appear repeatedly during forced operation, and does operating sound emit during indicating 50%?
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 5.
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 3.
3.CHECK PRIMARY UP 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. 2 — Transmission body:
Is the resistance approx. 10 — 13.5 ?? (when cold)
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 7.
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 4.
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?
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 7.
Repair the harness.
5.CHECK TRANSMISSION FLUID.
1) Connect the transmission connector.
2) Check the amount of ATF. CVTF > ADJUSTMENT">
Is the check result OK?
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 6.
Adjust the amount of ATF. CVTF > ADJUSTMENT">
6.CHECK TRANSMISSION FLUID.
Check the condition of ATF. CVTF > CONDITION CHECK">
Is the check result OK?
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 7.
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 P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 8.
Replace the transmission assembly. Automatic Transmission Assembly">
8.CHECK INPUT SIGNAL FOR TCM.
1) Set the select lever to “D” range.
2) Release the brake pedal to stabilize the engine speed and front wheel speed.
3) Read the data of «Actual Gear Ratio» using Subaru Select Monitor.
Is the «Actual Gear Ratio» 1.5 — 2.6?
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 9.
Replace the transmission assembly. Automatic Transmission Assembly">
9.CHECK INPUT SIGNAL FOR TCM.
1) Set the select lever to “D” range.
2) Slowly increase the speed to 40 km/h (25 MPH) and keep the constant speed.
3) Read the data of «Actual Gear Ratio» using Subaru Select Monitor.
Is the «Actual Gear Ratio» 0.5 — 0.9?
Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0751 SHIFT SOLENOID "A" PERFORMANCE/STUCK OFF">Go to Step 10.
Replace the transmission assembly. Automatic Transmission Assembly">
10.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 P0751 displayed?
Replace the transmission assembly. Automatic Transmission Assembly">
Current condition is normal. It is possible that temporary poor contact occurs.
1. OUTLINE OF DIAGNOSIS
• Detect the malfunction of shift-up fluid pressure control solenoid characteristics and hydraulic circuit characteristics (stuck to low pressure side).
• Judge as NG if the amount of gear rate change per second is equal to or larger than the predetermined value, even though the up-shift command is issued.
2. EXECUTION CONDITION
Secondary Parameters | Execution condition |
12 V battery system voltage | ≥ 10 V |
Engine speed | ≥ 1000 rpm |
Commanded duty of shift down pressure control solenoid | 0% |
Actual pulley ratio* | > 1.5 |
and | |
< 2.549 |
* Actual pulley ratio: Measured primary pulley shaft speed / Measured secondary pulley shaft speed
3. DIAGNOSTIC METHOD
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.
Malfunction Criteria | Threshold Value |
Actual pulley ratio change for 1 second | > − 0.08 |
Commanded duty of shift up pressure control solenoid | ≥ 90% |
Time Needed for Diagnosis: 1 second
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.
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