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Home >> Subaru >> 2006 >> Outback XT, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Engine (Diagnostics) (H4DOTC) >> Diagnostics for Engine Starting Failure >> Check Power Supply And Ground Line Of Engine Control Module (ECM)
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Check Power Supply And Ground Line Of Engine Control Module (ECM)

CAUTION: After repairing or replacing the defective part, perform the Clear Memory Mode < Ref. to OPERATION , Clear Memory Mode. > and Inspection Mode < Ref. to PROCEDURE , Inspection Mode. >.

WIRING DIAGRAM: 

Fig 1: Check Power Supply And Ground Line Of Engine Control Module - Wiring Diagram
G05021621
DIAGNOSTIC PROCEDURE

Step Check Yes No
1 CHECK MAIN RELAY. 
  1. Turn the ignition switch to OFF.
  2. Remove the main relay.
  3. Connect the battery to main relay terminals No. 1 and No. 2.
  4. Measure the resistance between main relay terminals.

    Terminals No. 3 - No. 5: 

    No. 4 - No. 6: 

 Is the resistance less than 10 Ω? Go to step 2.  Replace the main relay.
2 CHECK GROUND CIRCUIT FOR ECM. 
  1. Disconnect the connectors from ECM.
  2. Measure the resistance of harness between ECM and chassis ground.

    Connector & terminal 

    (B134) No. 6 - Chassis ground: 

    (B134) No. 7 - Chassis ground: 

    (B135) No. 1 - Chassis ground: 

    (B135) No. 4 - Chassis ground: 

    (B135) No. 12 - Chassis ground: 

    (B137) No. 1 - Chassis ground: 

    (B137) No. 2 - Chassis ground: 

    (B137) No. 3 - Chassis ground: 

    (B137) No. 7 - Chassis ground: 

 Is the resistance less than 5 Ω? Go to step 3.  Repair the open circuit of harness between ECM connector and engine grounding terminal.
3 CHECK INPUT VOLTAGE OF ECM. 
Measure the voltage between ECM connector and chassis ground.
Connector & terminal 
(B135) No. 19 (+) - Chassis ground (-): 		 Is the voltage more than 10 V? Go to step 4.  Repair the open or ground short circuit of power supply circuit.
4 CHECK INPUT VOLTAGE OF ECM. 
  1. Turn the ignition switch to ON.
  2. Measure the voltage between ECM connector and chassis ground.

    Connector & terminal 

    (B137) No. 14 (+) - Chassis ground (-): 

 Is the voltage more than 10 V? Go to step 5.  Repair the open or ground short circuit of power supply circuit.
5 CHECK INPUT VOLTAGE OF MAIN RELAY. 
Measure the voltage between main relay connector and chassis ground.
Connector & terminal 
(B47) No. 2 (+) - Chassis ground (-): 
(B47) No. 5 (+) - Chassis ground (-): 
(B47) No. 6 (+) - Chassis ground (-): 		 Is the voltage more than 10 V? Go to step 6.  Repair the open or ground short circuit of harness of power supply circuit.
6 CHECK INPUT VOLTAGE OF ECM. 
  1. Connect the main relay connector.
  2. Turn the ignition switch to ON.
  3. Measure the voltage between ECM connector and chassis ground.

    Connector & terminal 

    (B135) No. 5 (+) - Chassis ground (-): 

    (B135) No. 6 (+) - Chassis ground (-): 

 Is the voltage more than 10 V? Check ignition control system. < Ref. to IGNITION CONTROL SYSTEM , Diagnostics for Engine Starting Failure. > Repair the open or ground short circuit of harness between ECM connector and main relay connector.
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