Fuel Injector Circuit

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK OPERATION OF EACH FUEL INJECTOR  .

   While cranking the engine, check each fuel injector emits operating sound. Use a sound scope or attach a screwdriver to the injector to listen to sounds for this check.

   Does the fuel injector emit operating sound?

   Yes  : Check the fuel pressure. Ref. to MECHANICAL (H4DOTC)>FUEL PRESSURE>INSPECTION

   No  : Go to  2.

2. CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR (OPEN)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from ECM.
   3. Disconnect the connector from fuel injector.
   4. Measure the resistance of harness between ECM and fuel injector connector.

      Connector & terminal 

      #1 (E51) No. 15 - (E101) No. 1:

      #1 (E51) No. 16 - (E101) No. 2:

      #2 (E51) No. 31 - (E102) No. 1:

      #2 (E51) No. 32 - (E102) No. 2:

      #3 (E51) No. 47 - (E103) No. 1:

      #3 (E51) No. 48 - (E103) No. 2:

      #4 (E51) No. 63 - (E104) No. 1:

      #4 (E51) No. 64 - (E104) No. 2:

   Is the resistance less than 1 Ω?

   Yes  : Go to  3.

   No  : Repair the open circuit in harness between ECM and fuel injector connector.

3. CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR (SHORT TO GROUND)  .

   Measure the resistance between fuel injector connector and engine ground.

   Connector & terminal 

   #1 (E101) No. 1 - Engine ground:

   #1 (E101) No. 2 - Engine ground:

   #2 (E102) No. 1 - Engine ground:

   #2 (E102) No. 2 - Engine ground:

   #3 (E103) No. 1 - Engine ground:

   #3 (E103) No. 2 - Engine ground:

   #4 (E104) No. 1 - Engine ground:

   #4 (E104) No. 2 - Engine ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  4.

   No  : Repair the short circuit to ground in harness between ECM and fuel injector connector.

4. CHECK EACH FUEL INJECTOR  .

   Check each fuel injector. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>FUEL INJECTOR>INSPECTION

   Is the check result OK?

   Yes  : Repair the poor contact of ECM connector.

   No  : Replace the faulty fuel injector. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>FUEL INJECTOR