LEMON Manuals: Even more car manuals for everyone
Home >> Subaru >> 2006 >> Legacy GT spec.B >> Repair and Diagnosis >> External Pages >> Different car >> Section 63 (Engine Controls - Engine (Diagnostics) (H6DO)) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P0306 Cylinder 6 Misfire Detected

DTC P0306 Cylinder 6 Misfire Detected

WARNING: This page is about a different car, the 2006 Subaru Outback. However, it is still accessible from the selected car via links, so may be relevant.

DTC DETECTING CONDITION: 

TROUBLE SYMPTOM: 

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

WIRING DIAGRAM: 

Fig 1: Fuel Injector - Wiring Diagram
G05019024
DTC P0306 CYLINDER 6 MISFIRE DETECTED - DIAGNOSTIC PROCEDURE

Step Check Yes No
1 CHECK FOR ANY OTHER DTC ON DISPLAY.  Is any other DTC displayed? Check DTC using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >
NOTE: In this case, it is not necessary to inspect DTC P0301, P0302, P303, P0304, P0305 and P0306.
 Go to step 2. 
2 CHECK OUTPUT SIGNAL OF ECM. 
  1. Turn the ignition switch to ON.
  2. Measure the voltage between ECM connector and chassis ground on faulty cylinders.

    Connector & terminal 

    #1 (B137) No. 8 (+) - Chassis ground (-): 

    #2 (B137) No. 9 (+) - Chassis ground (-): 

    #3 (B137) No. 10 (+) - Chassis ground (-): 

    #4 (B137) No. 11(+) - Chassis ground (-): 

    #5 (B137) No. 12 (+) - Chassis ground (-): 

    #6 (B137) No. 13 (+) - 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. 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: 

    #5 (E43) No. 1 - Engine ground: 

    #6 (E44) No. 1 - Engine ground: 

 Is the resistance more than 1 MΩ? Go to step 4.  Repair the ground short circuit of 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 (B137) No. 8 - (E5) No. 1: 
#2 (B137) No. 9 - (E16) No. 1: 
#3 (B137) No. 10 - (E6) No. 1: 
#4 (B137) No. 11 - (E17) No. 1: 
#5 (B137) No. 12 - (E43) No. 1: 
#6 (B137) No. 13 - (E44) No. 2: 		 Is the resistance less than 1 Ω? Go to step 5.  Repair the harness and connector.
NOTE: In this case, repair the following item:
  • 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 between 5 and 20 Ω? 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 (-): 

    #5 (E43) No. 2 (+) - Engine ground (-): 

    #6 (E44) No. 2 (+) - Engine ground (-): 

 Is the voltage more than 10 V? Repair the poor contact of all connectors in fuel injector circuit. Repair the harness and connector.
NOTE: In this case, repair the following item:
  • Open circuit of harness between main relay and fuel injector 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 cylinders.
  3. Turn the ignition switch to ON.
  4. Measure the voltage between ECM connector and chassis ground on faulty cylinders.

    Connector & terminal 

    #1 (B137) No. 8 (+) - Chassis ground (-): 

    #2 (B137) No. 9 (+) - Chassis ground (-): 

    #3 (B137) No. 10 (+) - Chassis ground (-): 

    #4 (B137) No. 11(+) - Chassis ground (-): 

    #5 (B137) No. 12 (+) - Chassis ground (-): 

    #6 (B137) No. 13 (+) - Chassis ground (-): 

 Is the voltage more than 10 V? Repair the battery short circuit of 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 less than 1 Ω? Replace the faulty fuel injector < Ref. to FUEL INJECTOR . > and ECM. < Ref. to ENGINE CONTROL MODULE (ECM) . > Go to step 9. 
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 PLATE.  Is the crank sprocket rusted or the teeth of crank plate broken? Replace the crank plate. < Ref. to CYLINDER BLOCK . > Go to step 11. 
11 CHECK INSTALLATION CONDITION OF TIMING CHAIN. 
Turn the crankshaft using ST, and align alignment mark on crank sprocket with alignment mark on cylinder block.
ST 18252AA000 CRANKSHAFT SOCKET		 Is the timing chain dislocated from its proper position? Correct the installation condition of timing chain. < Ref. to TIMING CHAIN ASSEMBLY . > Go to step 12. 
12 CHECK FUEL LEVEL.  Is the fuel meter indication lower than the "Lower" level? Replenish fuel so fuel meter indication is higher than the "Lower" level. After replenishing fuel? Go to step 13.  Go to step 13. 
13 CHECK STATUS OF MALFUNCTION INDICATOR LIGHT. 
  1. Clear the memory using the Subaru Select Monitor or the general scan tool.
    NOTE:
    • Subaru Select Monitor

      < Ref. to SUBARU SELECT MONITOR . >

    • General scan tool

      Refer to operating manuals for the general scan tool.

  2. Start the engine, and drive the vehicle more than 10 minutes.
 Does the malfunction indicator light illuminate or blink? Go to step 15.  Go to step 14. 
14 CHECK CAUSE OF MISFIRE.  Was the cause of misfire identified when the engine is running? Finish diagnostics operation, if the engine has no abnormality. Repair the poor contact.
NOTE: In this case, repair the following item:
  • Poor contact of 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 MISFIRE SYMPTOM. 
  1. Turn the ignition switch to ON.
  2. READ DTC.

    < Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) . >

 Does the Subaru Select Monitor or general scan tool indicate only one DTC? Go to step 22.  Go to step 17. 
17 CHECK ANY OTHER DTC ON DISPLAY.  Are DTC P0301 and P0302 displayed? Go to step 23.  Go to step 18. 
18 CHECK DTC ON DISPLAY.  Are DTC P0303 and P0304 displayed? Go to step 24.  Go to step 19. 
19 CHECK DTC ON DISPLAY.  Are DTC P0305 and P0306 displayed? Go to step 25.  Go to step 20. 
20 CHECK DTC ON DISPLAY.  Are DTC P0301, P0303 and P0305 displayed? Go to step 26.  Go to step 21. 
21 CHECK DTC ON DISPLAY.  Are DTC P0302, P0304 and P0306 displayed? Go to step 27.  Go to step 28. 
22 ONLY ONE CYLINDER.  Is there any fault in the cylinder? Repair or replace faulty parts.
NOTE: Check the following items.
  • Spark plug
  • Fuel injector
  • Compression ratio
 Check DTC P0171, P0172, P0174 or P0175 using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >
23 GROUP OF #1 AND #2 CYLINDERS.  Are there any faults in #1 and #2 cylinders? Repair or replace faulty parts.
NOTE:
  • Check the following items.
    • Spark plug
    • Fuel injector
    • Ignition coil
    • Compression ratio
  • If any fault are not found, check the "IGNITION CONTROL SYSTEM" of #1 and #2 cylinders side.

< Ref. to IGNITION CONTROL SYSTEM , Diagnostics for Engine Starting Failure. >		 Check DTC P0171, P0172, P0174 or P0175 using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >
24 GROUP OF #3 AND #4 CYLINDERS.  Are there any faults in #3 and #4 cylinders? Repair or replace faulty parts.
NOTE:
  • Check the following items.
    • Spark plug
    • Fuel injector
    • Ignition coil
  • If any fault are not found, check the "IGNITION CONTROL SYSTEM" of #3 and #4 cylinders side.

< Ref. to IGNITION CONTROL SYSTEM , Diagnostics for Engine Starting Failure. >		 Check DTC P0171, P0172, P0174 or P0175 using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >
25 GROUP OF #5 AND #6 CYLINDERS.  Are there any faults in #5 and #6 cylinders? Repair or replace faulty parts.
NOTE:
  • Check the following items.
    • Spark plug
    • Fuel injector
    • Ignition coil
    • Compression ratio
  • If any fault are not found, check the "IGNITION CONTROL SYSTEM" of #5 and #6 cylinders side.

< Ref. to IGNITION CONTROL SYSTEM , Diagnostics for Engine Starting Failure. >		 Check DTC P0171, P0172, P0174 or P0175 using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >
26 GROUP OF #1, #3 AND #5 CYLINDERS.  Is there any fault in #1, #3 and #5 cylinders? Repair or replace faulty parts.
NOTE: Check the following items.
  • Spark plug
  • Fuel injector
  • Skipping timing chain teeth
 Check DTC P0171, P0172, P0174 or P0175 using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >
27 GROUP OF #2, #4 AND #6 CYLINDERS.  Is there any fault in #2, #4 and #6 cylinders? Repair or replace faulty parts.
NOTE: Check the following items.
  • Spark plug
  • Fuel injector
  • Compression ratio
  • Skipping timing chain teeth
 Check DTC P0171, P0172, P0174 or P0175 using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >
28 CYLINDER AT RANDOM.  Is the engine idle rough? Check DTC P0171, P0172, P0174 or P0175 using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . > Repair or replace faulty parts.
NOTE: Check the following items.
  • Spark plug
  • Fuel injector
  • Compression ratio
scientia non olet · About LEMON Manuals