Fuel Injector Circuit

CAUTION:

Check or repair only faulty parts.
After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>CLEAR MEMORY MODE and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>INSPECTION MODE .
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Engine Electrical System Ref. 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 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.
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 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 in harness between ECM and fuel injector connector.
CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR .
Measure the resistance of harness between ECM 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 and fuel injector connector.
CHECK EACH FUEL INJECTOR .
Check each fuel injector. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Fuel Injector>INSPECTION .

Is the check result OK?

Yes: Go to 5.

No: Replace the faulty fuel injector. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>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". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>GENERAL DIAGNOSTIC TABLE>INSPECTION .