Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p0730 incorrect gear ratio

Subaru Legacy BN/BS (2015-2019) Service Manual / Continuously variable transmission (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p0730 incorrect gear ratio

DTC DETECTING CONDITION:

Immediately at fault recognition

TROUBLE SYMPTOM:

• Acceleration is poor during standing start.

• Shift control malfunction

• Engine speed increases abruptly.

1. ENGINE TYPE FB

STEP	CHECK	YES	NO
1.CHECK TRANSMISSION FLUID. Check the amount of ATF. CVTF > ADJUSTMENT	Is the ATF amount correct-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0730 INCORRECT GEAR RATIO	Adjust the amount of ATF. CVTF > ADJUSTMENT
2.CHECK TRANSMISSION FLUID. Check the condition of ATF. CVTF > CONDITION CHECK	Is the ATF OK-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0730 INCORRECT GEAR RATIO	Check according to the “Corrective action” of ATF (CVTF) “CONDITION CHECK”. CVTF > CONDITION CHECK
3.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 P0730 INCORRECT GEAR RATIO	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
4.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 P0730 INCORRECT GEAR RATIO	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0730 INCORRECT GEAR RATIO
5.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 P0730 INCORRECT GEAR RATIO	Replace the transmission assembly. Automatic Transmission Assembly
6.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 P0730 displayed-	Replace the transmission assembly. Automatic Transmission Assembly	Current condition is normal. It is possible that temporary poor contact occurs.

2. ENGINE TYPE EZ

STEP	CHECK	YES	NO
1.CHECK TRANSMISSION FLUID. Check the amount of ATF. CVTF > ADJUSTMENT	Is the ATF amount correct-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0730 INCORRECT GEAR RATIO	Adjust the amount of ATF. CVTF > ADJUSTMENT
2.CHECK TRANSMISSION FLUID. Check the condition of ATF. CVTF > CONDITION CHECK	Is the ATF OK-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0730 INCORRECT GEAR RATIO	Check according to the “Corrective action” of ATF (CVTF) “CONDITION CHECK”. CVTF > CONDITION CHECK
3.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 P0730 INCORRECT GEAR RATIO	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
4.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» 2.0 — 2.4-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0730 INCORRECT GEAR RATIO	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0730 INCORRECT GEAR RATIO
5.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 — 0.8-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0730 INCORRECT GEAR RATIO	Replace the transmission assembly. Automatic Transmission Assembly
6.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 P0730 displayed-	Replace the transmission assembly. Automatic Transmission Assembly	Current condition is normal. It is possible that temporary poor contact occurs.

3. OUTLINE OF DIAGNOSIS

• Detect the abnormality in transmission gear ratio control function.

• Judge as NG if a discrepancy between the transmission target gear ratio (as internal data) and the actual gear ratio becomes the specified value or more. (Compare the value of “Gear Ratio Target - Secondary pulley speed ≈ Target primary speed equivalent value” with the value of primary pulley speed sensor.)

4. EXECUTION CONDITION

Secondary Parameters	Execution condition
12 V battery system voltage	≥ 10 V
Engine speed	≥ 500 rpm
Transmission range	Drive

5. DIAGNOSTIC METHOD

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
\|Target primary pulley shaft speed − Measured primary pulley shaft speed\|	≥ 600 rpm
(Commanded duty of shift up pressure control solenoid valve	≥ 90%
or
Commanded duty of shift down pressure control solenoid valve)	≥ 90%

Time Needed for Diagnosis: 5 seconds

Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.

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