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Diagnostic Procedure

  1. 8D1: CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR. 
    1. Turn ignition switch to OFF.
    2. Disconnect connector from transmission.
    3. Measure resistance of harness between TCM and transmission connector.

    Connector & Terminal 

    (B55) No. 10 - (B11) No. 12: 

    Fig 1: Measuring Resistance Of Harness Between TCM & Transmission Connector
    G02003477

    CHECK: Is the resistance less than 1 ohm? 

    1. YES:  Go to step 8D2. 
    2. NO:  Repair open circuit in harness between TCM and transmission connector.
  2. 8D2: CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR. 

    Measure resistance of harness between TCM and transmission connector.

    Connector & Terminal 

    (B55) No. 11 - (B11) No. 11: 

    Fig 2: Measuring Resistance Of Harness Between TCM & Transmission Connector
    G02003478

    CHECK: Is the resistance less than 1 ohm? 

    1. YES:  Go to step 8D3. 
    2. NO:  Repair open circuit in harness between TCM and transmission connector.
  3. 8D3: CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR. 

    Measure resistance of harness between TCM connector and chassis ground.

    Connector & Terminal 

    (B55) No. 10 - Chassis ground: 

    Fig 3: Measuring Resistance Of Harness Between TCM Connector & Chassis Ground
    G02003479

    CHECK: Is the resistance more than 1 Mohm? 

    1. YES:  Go to step 8D4. 
    2. NO:  Repair short circuit in harness between TCM and transmission connector.
  4. 8D4: CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR. 

    Measuring resistance of harness between TCM connector and chassis ground.

    Connector & Terminal 

    (B55) No. 11 - Chassis ground: 

    Fig 4: Measuring Resistance Of Harness Between TCM connector & Chassis Ground
    G02003480

    CHECK: Is the resistance more than 1 Mohm? 

    1. YES:  Go to step 8D5. 
    2. NO:  Repair short circuit in harness between TCM and transmission connector.
  5. 8D5: CHECK ATF TEMPERATURE SENSOR. 
    1. Turn ignition switch to OFF.
    2. Connect connectors to transmission.
    3. Turn ignition switch to ON and start engine.
    4. Warm-up the transmission until ATF temperature reaches to 80°C (176°F).
      NOTE: If ambient temperature is below 0°C (32°F), drive the vehicle until the ATF reaches its operating temperature.
    5. Disconnect connector from transmission.
    6. Measuring resistance between transmission connector terminals.

    Connector & Terminal 

    (T4) No. 11 - No. 12: 

    Fig 5: Measuring Resistance Between Transmission Connector Terminals
    G02003481

    CHECK: Is the resistance between 275 and 375 ohm? 

    1. YES:  Go to step 8D6. 
    2. NO:  Go to step  8D13.
  6. 8D6: CHECK ATF TEMPERATURE SENSOR. 
    1. Turn ignition switch to ON (engine OFF).
    2. Measuring resistance between transmission connector terminals.

    Connector & Terminal 

    (T4) No. 11 - No. 12: 

    Fig 6: Measuring Resistance Between Transmission Connector Terminals
    G02003482

    CHECK: Does the resistance value increase while the ATF temperature decreases? 

    1. YES:  Go to step 8D7. 
    2. NO:  Go to step  8D13.
  7. 8D7: PREPARE SUBARU SELECT MONITOR. 

    CHECK: Do you have a Subaru Select Monitor? 

    1. YES:  Go to step  8D10.
    2. NO:  Go to step 8D8. 
  8. 8D8: CHECK INPUT SIGNAL FOR TCM. 
    1. Warm-up the transmission until ATF temperature is about 80°C (176°F).
      NOTE: If ambient temperature is below 0°C (32°F), drive the vehicle until the ATF reaches its operating temperature.
    2. Measuring voltage between TCM connector terminal.

    Connector & Terminal 

    (B55) No. 11 (+) - No. 10 (-): 

    Fig 7: Measuring Voltage Between TCM Connector Terminal
    G02003483

    CHECK: Is the voltage between 0.5 and 0.8 V? 

    1. YES:  Go to step 8D9. 
    2. NO:  Go to step  8D12.
  9. 8D9: CHECK INPUT SIGNAL FOR TCM. 
    1. Cool-down the transmission until ATF temperature is under 20°C (68°F).
    2. Measuring voltage between TCM connector terminal.

    Connector & Terminal 

    (B55) No. 11 (+) - No. 10 (-): 

    Fig 8: Measuring Voltage Between TCM Connector Terminal
    G02003484

    CHECK: Is the voltage between 2.9 and 4.9 V? 

    1. YES:  Even if "AT OIL TEMP" lights up, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector or harness may be the cause. Repair harness or contact in the ATF temperature sensor or transmission connector.
    2. NO:  Go to step  8D12.
  10. 8D10: CHECK INPUT SIGNAL FOR TCM USING SUBARU SELECT MONITOR. 
    1. Turn ignition switch to OFF.
    2. Connect connector to transmission.
    3. Connect Subaru Select Monitor to data link connector.
      Fig 9: Identifying Location Data Link Connector (DLC)
      G02003485
    4. Start the engine, and turn Subaru Select Monitor switch to ON.
    5. Warm-up the transmission until ATF temperature is above 80°C (176°F).
      NOTE: If ambient temperature is below 0°C (32°F), drive the vehicle until the ATF reaches its operating temperature.
    6. Read data of ATF temperature using Subaru Select Monitor.
    • ATF temperature is indicated in "°F" or "°C".

    CHECK: Is the ATF temperature between 70 and 110°C (158 and 230°F). 

    1. YES:  Go to step 8D11. 
    2. NO:  Go to step  8D12 .
  11. 8D11: CHECK INPUT SIGNAL FOR TCM USING SUBARU SELECT MONITOR. 

    Turn ignition switch to ON (engine OFF).

    CHECK: Does the ATF temperature gradually decrease? 

    1. YES:  Even if "AT OIL TEMP" light up, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector or harness may be the case. Repair harness or contact in the ATF temperature sensor and transmission connector.
    2. NO:  Go to step 8D12. 
  12. 8D12: CHECK POOR CONTACT. 

    CHECK: Is there poor contact in ATF temperature sensor circuit? 

    1. YES:  Repair poor contact.
    2. NO:  Replace TCM, see TRANSMISSION CONTROL MODULE (TCM) .
  13. 8D13: CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND ATF TEMPERATURE SENSOR. 
    1. Turn ignition switch to OFF.
    2. Disconnect connector from transmission.
    3. Remove transmission connector from stay.
    4. Lift-up or raise the vehicle and support with safety stand.
      CAUTION: On AWD models, raise all wheels off ground.
    5. Drain automatic transmission fluid.
      CAUTION: Do not drain the automatic transmission fluid until it cools down.
    6. Remove oil pan, and disconnect connector from ATF temperature sensor connector.
    7. Measuring resistance of harness between ATF temperature sensor and transmission connector.

    Connector & Terminal 

    (T4) No. 11 - (AT1) No. 2: 

    Fig 10: Measuring Resistance Of Harness Between ATF Temperature Sensor & Transmission Connector
    G02003486

    CHECK: Is the resistance less than 1 ohm? 

    1. YES:  Go to step 8D14. 
    2. NO:  Repair open circuit in harness between ATF temperature sensor and transmission connector.
  14. 8D14: CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND ATF TEMPERATURE SENSOR. 

    Measuring resistance of harness between ATF temperature sensor and transmission connector.

    Connector & Terminal 

    (T4) No. 12 - (AT1) No. 1: 

    Fig 11: Measuring Resistance Of Harness Between ATF Temperature Sensor & Transmission Connector
    G02003487

    CHECK: Is the resistance less than 1 ohm? 

    1. YES:  Go to step 8D15. 
    2. NO:  Repair open circuit in harness between ATF temperature sensor and transmission connector.
  15. 8D15: CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND ATF TEMPERATURE SENSOR. 

    Measuring resistance of harness between transmission connector and transmission ground.

    Connector & Terminal 

    (T4) No. 11 - Transmission ground: 

    Fig 12: Measuring Resistance Of Harness Between Transmission Connector & Transmission Ground
    G02003488

    CHECK: Is the resistance more than 1 Mohm? 

    1. YES:  Go to step 8D16. 
    2. NO:  Repair short circuit in harness between ATF temperature sensor and transmission connector.
  16. 8D16: CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND ATF TEMPERATURE SENSOR. 

    Measuring resistance of harness between transmission connector and transmission ground.

    Connector & Terminal 

    (T4) No. 12 - Transmission ground: 

    Fig 13: Measuring Resistance Of Harness Between Transmission Connector & Transmission Ground
    G02003489

    CHECK: Is the resistance more than 1 Mohm? 

    1. YES:  Replace ATF temperature sensor.
    2. NO:  Repair short circuit in harness between ATF temperature sensor and transmission connector.
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