At Model

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .

Fig 1: AT Model Engine Electrical System Wiring Diagram (Park/Neutral Switch Input Circuit Low)

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK SELECT CABLE  .

   Is there any fault in select cable?

   • Yes: Repair or adjust the select cable. Ref. to CONTROL SYSTEMS>Select Cable .
   • No: Go to  2.
2. CHECK INPUT SIGNAL OF ECM  .
   1. Turn the ignition switch to ON.
   2. Place the select lever in other than "P" range and "N" range.
   3. Measure the voltage between ECM connector and chassis ground.

   Connector & terminal 

   (B134) No. 5 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   • Yes: Repair the poor contact of ECM connector.
   • No: Go to  3.
3. CHECK HARNESS BETWEEN ECM AND TRANSMISSION HARNESS CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connectors from ECM and transmission harness connector (T3).
   3. Measure the resistance between ECM connector and chassis ground.

      Connector & terminal 

      (B134) No. 5 - Chassis ground:

      Is the resistance 1 MΩ or more?

      • Yes: Go to  4.
      • No: Repair the short circuit to ground in harness between ECM connector and transmission harness connector.
4. CHECK TRANSMISSION HARNESS CONNECTOR  .

1. Disconnect the connector from inhibitor switch.
2. Measure the resistance between transmission harness connector and engine ground.

Connector & terminal 

(T3) No. 16 - Engine ground:

Is the resistance 1 MΩ or more?

• Yes: Replace the inhibitor switch. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580)>Inhibitor Switch .
• No: Repair short circuit to ground in harness between transmission harness connector and inhibitor switch connector.