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Diagnostic Procedure

WARNING: This page is about a different car, the 2013 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.
DIAGNOSTIC PROCEDURE

Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connectors from TCM and transmission.
  3. Measure the resistance of harness between TCM connector and transmission connector.

    Connector & terminal 

    (B55) No. 3 - (B11) No. 2: 

    (B55) No. 4 - (B11) No. 1: 

 Is the resistance less than 1 Ω? Go to step 2  . Repair the open circuit of harness between TCM and transmission connector.
2 CHECK HARNESS CONNECTOR BETWEEN TCM AND CHASSIS GROUND. 
Measure the resistance of harness between TCM connector and chassis ground.
Connector & terminal 
(B55) No. 3 - Chassis ground: 
(B55) No. 4 - Chassis ground: 		 Is the resistance 1 MΩ or more? Go to step 3  . Repair the short circuit of harness between TCM and transmission connector.
3 CHECK LINE PRESSURE LINEAR SOLENOID. 
Measure the resistance between transmission connector terminals.
Connector & terminal 
(T4) No. 1 - No. 2: 		 Is the resistance 4.0 - 8.0 Ω? Replace the TCM. < Refer to TRANSMISSION CONTROL MODULE (TCM) . > Go to step 4  .
4 CHECK LINE PRESSURE LINEAR SOLENOID (IN TRANSMISSION). 
  1. Remove the transmission connector from bracket.
  2. Drain the automatic transmission fluid.
    CAUTION: Do not drain ATF until it cools down.
  3. Remove the oil pan.
  4. Disconnect the connector from the control valve body.
  5. Measure the resistance of line pressure linear solenoid connector terminals.

    Connector & terminal 

    (AT2) No. 5 - No. 10: 

 Is the resistance 4.0 - 8.0 Ω? Go to step 5  . Replace the control valve body. < Refer to CONTROL VALVE BODY . >
5 CHECK HARNESS CONNECTOR BETWEEN LINE PRESSURE LINEAR SOLENOID AND TRANSMISSION. 
Measure the resistance of harness between line pressure linear solenoid and transmission connector.
Connector & terminal 
(T4) No. 1 - (AT2) No. 5: 
(T4) No. 2 - (AT2) No. 10: 		 Is the resistance less than 1 Ω? Go to step 6  . Repair the open circuit of harness between line pressure linear solenoid and transmission connector.
6 CHECK HARNESS CONNECTOR BETWEEN LINE PRESSURE LINEAR SOLENOID AND TRANSMISSION. 
Measure the resistance of harness between transmission connector and transmission ground.
Connector & terminal 
(T4) No. 1 - Transmission ground: 
(T4) No. 2 - Transmission ground: 		 Is the resistance 1 MΩ or more? Check the harnesses or connectors between line pressure linear solenoid and transmission, and repair the defective part. Repair the short circuit of harness between line pressure linear solenoid and transmission connector.
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