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Home >> Subaru >> 2005 >> Forester XS, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Engine (Diagnostics) (H4SO) >> Diagnostics for Engine Starting Failure >> Fuel Injector Circuit

Fuel Injector Circuit

CAUTION:
  • Check or repair only faulty parts.
  • After repair or replacement of faulty parts, conduct Clear Memory Mode < Ref. to , OPERATION , Clear Memory Mode. > and Inspection Mode < Ref. to , PROCEDURE , Inspection Mode. >.

WIRING DIAGRAM: 

Fig 1: Fuel Injector Circuit Wiring Diagram
G03806035Courtesy of SUBARU OF AMERICA, INC.
DIAGNOSTIC STEPS INJECTOR

Step Check Yes No
1 CHECK OPERATION OF EACH FUEL INJECTOR. 
While cranking the engine, check that each fuel injector emits "operating" sound. Use a sound scope or attach a screwdriver to the injector for this check.
Dose the fuel injector operate? Check the fuel pressure. < Ref. to INSPECTION , Fuel Pressure . > Go to step .
2 CHECK POWER SUPPLY TO EACH FUEL INJECTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from fuel injector.
  3. Turn the ignition switch to ON.
  4. Measure the power supply voltage between the fuel injector terminal and engine ground.

Connector & terminal 
#1 (E5) No. 2 (+) - Engine ground (-): 
#2 (E16) No. 2 (+) - Engine ground (-): 
#3 (E6) No. 2 (+) - Engine ground (-): 
#4 (E17) No. 2 (+) - Engine ground (-): 
Is the voltage more than 10 V? Go to step . Repair harness and connector.
NOTE: In this case, repair the following:
  • Open circuit in harness between main relay and fuel injector connector
  • Poor contact in main relay connector
  • Poor contact in coupling connector (B22)
  • Poor contact in fuel injector connector
3 CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR. 
  1. Disconnect the connector from ECM.
  2. Measure the resistance of harness between ECM and fuel injector connector.

Connector & terminal 
#1 (B136) No. 6 - (E5) No. 1: 
#2 (B136) No. 5 - (E16) No. 1: 
#3 (B136) No. 4 - (E6) No. 1: 
#4 (B136) No. 3 - (E17) No. 1: 
Is the resistance less than 1 Ω? Go to step . Repair harness and connector.
NOTE: In this case, repair the following:
  • Open circuit in harness between ECM and fuel injector connector
  • Poor contact in coupling connector
4 CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR. 
Measure the resistance of harness between ECM and fuel injector connector.
Connector & terminal 
#1 (B136) No. 6 - Chassis ground: 
#2 (B136) No. 5 - Chassis ground: 
#3 (B136) No. 4 - Chassis ground: 
#4 (B136) No. 3 - Chassis ground: 
Is the resistance more than 1 MΩ? Go to step . Repair ground short circuit in harness between ECM and fuel injector connector.
5 CHECK EACH FUEL INJECTOR. 
  1. Turn the ignition switch to OFF.
  2. Measure the resistance between each fuel injector terminals.
Terminals 
No. 1 - No. 2: 
Is the resistance 5 - 20 Ω? Go to step . Replace the faulty fuel injector.
6 CHECK POOR CONTACT. 
Check poor contact in ECM connector.
Is there poor contact in ECM connector? Repair poor contact in ECM connector. Inspection using "General Diagnostic Table". < Ref. to INSPECTION , General Diagnostic Table. >