Fuel Injector Circuit

Wiring diagram:

Engine Electrical System Refer to WIRING SYSTEM (IMPREZA MODEL)>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM . Refer to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Check or repair only faulty parts.
Use the check board when measuring the ECM terminal voltage and resistance. Refer to ENGINE (DIAGNOSTICS) (H4DO (EXCEPT FOR HEV))>General Description>PREPARATION TOOL>HOW TO USE CHECK BOARD .

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. Refer to MECHANICAL (H4DO (EXCEPT FOR HEV))>FUEL PRESSURE>INSPECTION .

No: Go to 2.
CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR .
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 (E158) No. 96 - (E5) No. 1:
  
  #1 (E158) No. 87 - (E5) No. 2:
  
  #2 (E158) No. 95 - (E16) No. 1:
  
  #2 (E158) No. 86 - (E16) No. 2:
  
  #3 (E158) No. 93 - (E6) No. 1:
  
  #3 (E158) No. 84 - (E6) No. 2:
  
  #4 (E158) No. 94 - (E17) No. 1:
  
  #4 (E158) No. 85 - (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 .
Measure the resistance between fuel injector connector and engine ground.

Connector & terminal

#1 (E5) No. 1 - Engine ground:

#1 (E5) No. 2 - Engine ground:

#2 (E16) No. 1 - Engine ground:

#2 (E16) No. 2 - Engine ground:

#3 (E6) No. 1 - Engine ground:

#3 (E6) No. 2 - Engine ground:

#4 (E17) No. 1 - Engine ground:

#4 (E17) 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.
CHECK EACH FUEL INJECTOR .
Check each fuel injector. Refer to FUEL INJECTION (FUEL SYSTEMS) (H4DO (EXCEPT FOR HEV))>FUEL INJECTOR>INSPECTION .

Is the check result OK?

Yes: Repair the poor contact of ECM connector.

No: Replace the faulty fuel injector. Refer to FUEL INJECTION (FUEL SYSTEMS) (H4DO (EXCEPT FOR HEV))>FUEL INJECTOR .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Refer to ENGINE (DIAGNOSTICS) (H4DO (EXCEPT FOR HEV))>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .