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Home >> Subaru >> 2005 >> Outback R VDC Limited >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 22 (Engine Controls - Engine (Diagnostics) (H4DOTC)) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P0304 Cylinder 4 Misfire Detected >> Wiring Diagram:

Wiring Diagram:

WARNING: This page is about a different variant/trim than selected.
Fig 1: Wiring Diagram - DTC P0304 Cylinder 4 Misfire Detected
G03830008Courtesy of SUBARU OF AMERICA, INC.
DIAGNOSTIC PROCEDURE (DTC P0304)

Step Check Yes No
1 
CHECK FOR ANY OTHER DTC ON DISPLAY. 		 Is any other DTC displayed? Inspect the relevant DTC using "List of Diagnostic Trouble Code (DTC)". < Ref. to , LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . > Go to step 2. 
2 
CHECK OUTPUT SIGNAL FROM ECM. 
  1. Turn the ignition switch to ON.
  2. Measure the voltage between ECM connector and chassis ground on faulty cylinders.

    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 voltage more than 10 V? Go to step 7.  Go to step 3. 
3 
CHECK HARNESS BETWEEN FUEL INJECTOR AND ECM CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from fuel injector on faulty cylinders.
  3. Disconnect the connector from ECM.
  4. Measure the resistance between ECM connector and engine ground on faulty cylinders.

    Connector & terminal 

    #1 (E5) No. 1 - Engine ground: 

    #2 (E16) No. 1 - Engine ground: 

    #3 (E6) No. 1 - Engine ground: 

    #4 (E17) No. 1 - Engine ground: 

 Is the resistance more than 1 M? Go to step 4.  Repair the ground short circuit in harness between fuel injector and ECM connector.
4 
CHECK HARNESS BETWEEN FUEL INJECTOR AND ECM CONNECTOR. 
Measure the resistance of harness connector between ECM connector and fuel injector on faulty cylinders.
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 ? Go to step 5.  Repair the 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
5 
CHECK FUEL INJECTOR. 
Measure the resistance between fuel injector terminals on faulty cylinder.
Terminals 
No. 1 - No. 2: 		 Is the resistance 5 - 20 ? Go to step 6.  Replace the faulty fuel injector. < Ref. to FUEL INJECTOR . >
6 
CHECK POWER SUPPLY LINE. 
  1. Turn the ignition switch to ON.
  2. Measure the voltage between fuel injector and engine ground on faulty cylinders.

    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? Repair the poor contact in all connectors in fuel injector circuit. Repair the harness and connector.
NOTE: In this case, repair the following:
  • Open circuit in harness between main relay and fuel injector connector on faulty cylinders
  • Poor contact in coupling connector
  • Poor contact in main relay connector
  • Poor contact in fuel injector connector on faulty cylinders
7 
CHECK HARNESS BETWEEN FUEL INJECTOR AND ECM CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from fuel injector on faulty cylinder.
  3. Turn the ignition switch to ON.
  4. Measure the voltage between ECM connector and chassis ground on faulty cylinders.

    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 voltage more than 10 V? Repair the battery short circuit in harness between ECM and fuel injector. After repair, replace the ECM. < Ref. to ENGINE CONTROL MODULE (ECM) . > Go to step 8. 
8 
CHECK FUEL INJECTOR. 
  1. Turn the ignition switch to OFF.
  2. Measure the resistance between fuel injector terminals on faulty cylinder.

    Terminals No. 

    1 - No. 2: 

 Is the resistance 5 - 20 ? Go to step 9.  Replace the faulty fuel injector < Ref. to FUEL INJECTOR .> and ECM < Ref. to , ENGINE CONTROL MODULE (ECM) . >
9 
CHECK INSTALLATION OF CAMSHAFT POSITION SENSOR/CRANKSHAFT POSITION SENSOR. 		 Is the camshaft position sensor or crankshaft position sensor loosely installed? Tighten the camshaft position sensor or crankshaft position sensor. Go to step 10. 
10 
CHECK CRANK SPROCKET. 
Remove the timing belt cover.		 Is the crank sprocket rusted or does it have broken teeth? Replace the crank sprocket. < Ref. to CRANK SPROCKET . > Go to step 11. 
11 
CHECK INSTALLATION CONDITION OF TIMING BELT. 
Turn the crankshaft, and align alignment mark on crank sprocket with alignment mark on cylinder block.		 Is the timing belt dislocated from its proper position? Repair the installation condition of timing belt. < Ref. to TIMING BELT . > Go to step 12. 
12 
CHECK FUEL LEVEL. 		 Is the fuel meter indication higher than the "Lower" level? Go to step 13.  Replenish the fuel so fuel meter indication is higher than the "Lower" level. After replenishing fuel; Go to step 13. 
13 
CHECK STATUS OF MALFUNCTION INDICATOR LIGHT. 
  1. Clear the memory using Subaru Select Monitor.

    < Ref. to , CLEAR MEMORY MODE . >

  2. Start the engine, and drive the vehicle more than 10 minutes.
 Is the malfunction indicator light coming on or blinking? Go to step 15.  Go to step 14. 
14 
CHECK CAUSE OF MISFIRE DIAGNOSED. 		 Was the cause of misfire diagnosed when the engine is running? Finish the diagnostics operation, if the engine has no abnormality. Repair the poor contact.
NOTE: In this case, repair the following:
  • Poor contact in ignition coil connector
  • Poor contact in fuel injector connector on faulty cylinders
  • Poor contact in ECM connector
  • Poor contact in coupling connector
15 
CHECK AIR INTAKE SYSTEM. 		 Is there any fault in air intake system? Repair the air intake system.
NOTE: Check the following items:
  • Are there air leaks or air suction caused by loose or dislocated nuts and bolts?
  • Are there cracks or any disconnection of hoses?
 Go to step 16. 
16 
CHECK CYLINDER. 		 Is there any fault in that cylinder? Repair or replace the faulty parts.
NOTE: Check the following items.
  • Spark plug
  • Fuel injector
  • Compression pressure
 Go to DTC P0171 and P0172.

< Ref. to , DTC P0171 SYSTEM TOO LEAN (BANK 1) , Diagnostic Procedure with Diagnostic Trouble Code (DTC). >
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