Fuel Injector Circuit

CAUTION:

Check or repair only faulty parts.
After servicing or replacing faulty parts, perform Clear Memory Mode Refer to ENGINE (DIAGNOSTICS) (W/O STI)>CLEAR MEMORY MODE>OPERATION ., and inspection mode Refer to ENGINE (DIAGNOSTICS) (W/O STI)>INSPECTION MODE>PROCEDURE .
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

CHECK OPERATION OF EACH FUEL INJECTOR.
While cranking the engine, check each fuel injector emits operating sound. Use a sound scope or listen by attaching a screwdriver to the injector for this check.

Does the fuel injector emit operating sound?

Yes: Check the fuel pressure. Refer to MECHANICAL(W/O STI)>FUEL PRESSURE>INSPECTION .

No: Go to 2.
CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the resistance of harness between ECM connector and fuel injector connector.
  Connector & terminal
  
  #1 (E158) No. 12 - (E5) No. 1:
  
  #1 (E158) No. 11 - (E5) No. 2:
  
  #2 (E158) No. 24 - (E16) No. 1:
  
  #2 (E158) No. 23 - (E16) No. 2:
  
  #3 (E158) No. 36 - (E6) No. 1:
  
  #3 (E158) No. 35 - (E6) No. 2:
  
  #4 (E158) No. 48 - (E17) No. 1:
  
  #4 (E158) No. 47 - (E17) No. 2:
Is the resistance less than 1 Ω?

Yes: Go to 3.

No: Repair the open circuit of the harness between the ECM connector and fuel injector connector.
CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR.
Measure the resistance of harness between ECM connector and chassis ground.

Connector & terminal

#1 (E158) No. 12 - Chassis ground:

#1 (E158) No. 11 - Chassis ground:

#2 (E158) No. 24 - Chassis ground:

#2 (E158) No. 23 - Chassis ground:

#3 (E158) No. 36 - Chassis ground:

#3 (E158) No. 35 - Chassis ground

#4 (E158) No. 48 - Chassis ground:

#4 (E158) No. 47 - 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 fuel injector connector.
CHECK EACH FUEL INJECTOR.
Check each fuel injector. Refer to FUEL INJECTION (FUEL SYSTEMS) (W/O STI)>FUEL INJECTOR>INSPECTION .

Is the check result OK?

Yes: Go to 5.

No: Replace the faulty fuel injector. Refer to FUEL INJECTION (FUEL SYSTEMS) (W/O STI)>FUEL INJECTOR .
CHECK FOR POOR CONTACT.
Check for poor contact of ECM connector.

Is there poor contact of ECM connector?

Yes: Repair the poor contact of ECM connector.

No: Inspection using "General Diagnostic Table" Refer to ENGINE (DIAGNOSTICS) (W/O STI)>GENERAL DIAGNOSTIC TABLE>INSPECTION .