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DTC P0201: Cylinder 1 Injector "A" Circuit: Notes

DTC detecting condition: 

Immediately at fault recognition

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .
NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

G16527868Courtesy of SUBARU OF AMERICA, INC.
  1. CHECK DTC  .
    1. Turn the ignition switch to ON.
    2. Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

    When DTC P0201 (current code), P0202 (current code), P0203 (current code), or P0204 (current code) is displayed, go to  A.

    When DTC P0201 (current code), P0202 (current code), P0203 (current code), and P0204 (current code) are all displayed, go to  B.

    When a code other than DTC P0201 (current code), P0202 (current code), P0203 (current code), or P0204 (current code) is displayed, go to  C.

    1. Go to  2.
    2. Go to  6.
    3. Check the appropriate DTC using the "Diagnostic Trouble Code (DTC)". Ref. to ENGINE (DIAGNOSTICS) (H4DO)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .
  2. CHECK POWER SUPPLY FOR FUEL INJECTOR (FOR PORT INJECTION)  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from the fuel injector (for port injection).
    3. Turn the ignition switch to ON.
    4. Measure the voltage between the fuel injector (for port injection) connector and the engine ground.

      Connector & terminal 

      DTC P0201; (E131) No. 1 (+) - Engine ground (-):

      DTC P0202; (E132) No. 1 (+) - Engine ground (-):

      DTC P0203; (E133) No. 1 (+) - Engine ground (-):

      DTC P0204; (E134) No. 1 (+) - Engine ground (-):

    Is the voltage 11 - 14 V?

    Yes:  Go to  3.

    No:  Go to  6.

  3. CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR (FOR PORT INJECTION) CONNECTOR (OPEN)  .
    1. Disconnect the connector from ECM.
    2. Measure the resistance of the harness between ECM connector and fuel injector (for port injection) connector.

      Connector & terminal 

      DTC P0201; (E53) No. 98 - (E131) No. 2:

      DTC P0202; (E53) No. 97 - (E132) No. 2:

      DTC P0203; (E53) No. 107 - (E133) No. 2:

      DTC P0204; (E53) No. 106 - (E134) No. 2:

    Is the resistance less than 1 Ω?

    Yes:  Go to  4.

    No:  Repair the open circuit of the harness between the ECM connector and fuel injector (for port injection) connector.

  4. CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR (FOR PORT INJECTION) CONNECTOR (SHORT TO GROUND)  .

    Measure the resistance between the ECM connector and engine ground.

    Connector & terminal 

    DTC P0201; (E53) No. 98 - Engine ground:

    DTC P0202; (E53) No. 97 - Engine ground:

    DTC P0203; (E53) No. 107 - Engine ground:

    DTC P0204; (E53) No. 106 - Engine ground:

    Is the resistance 1 MΩ or more?

    Yes:  Go to  5.

    No:  Repair the short circuit to ground in the harness between ECM connector and fuel injector (for port injection) connector.

  5. CHECK FUEL INJECTOR (FOR PORT INJECTION)  .

    Check the fuel injector (for port injection). Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>FUEL INJECTOR>INSPECTION .

    Is the check result OK?

    Yes:  Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM) .

    No:  Replace the faulty fuel injector (for port injection). Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>FUEL INJECTOR .

  6. CHECK MAIN RELAY  .
    1. Turn the ignition switch to OFF.
    2. Remove the main relay.
    3. Check the main relay. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>MAIN RELAY>INSPECTION .

    Is the check result OK?

    Yes:  Go to  7.

    No:  Replace the main relay. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>MAIN RELAY

  7. CHECK HARNESS BETWEEN MAIN RELAY AND FUEL INJECTOR (FOR PORT INJECTION) CONNECTOR (OPEN)  .

    Measure the resistance of harness between M/B (main relay) terminal No. 3 and fuel injector (for port injection) connector.

    Connector & terminal 

    DTC P0201; No. 3 - (E131) No. 1:

    DTC P0202; No. 3 - (E132) No. 1:

    DTC P0203; No. 3 - (E133) No. 1:

    DTC P0204; No. 3 - (E134) No. 1:

    Is the resistance less than 1 Ω?

    Yes:  Go to  8.

    No:  Repair the following item.

    • Open circuit in harness between M/B (main relay) and fuel injector (for port injection) connector
    • Blown out of fuse
    • Poor contact of J/C
    • Poor contact of coupling connector
  8. CHECK HARNESS BETWEEN MAIN RELAY AND FUEL INJECTOR (FOR PORT INJECTION) CONNECTOR (SHORT TO GROUND)  .

    Measure the resistance of harness between M/B (main relay) terminal No. 3 and fuel injector (for port injection) connector.

    Connector & terminal 

    No: 3 - Engine ground:

    Is the resistance 1 MΩ or more?

    Yes:  Check the engine control module (ECM) power supply and ground line. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>DIAGNOSTICS WITH PHENOMENON>CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE (ECM) .

    No:  Repair the short circuit to ground in harness between M/B (main relay) and fuel injector (for port injection) connector.

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