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HOMESERVICE MANUALSSUBARU2014IMPREZA SPORT LIMITEDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROL SYSTEM (DIAGNOSTICS) (EXCEPT HYBRID)DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)DTC P0103: MASS OR VOLUME AIR FLOW CIRCUIT HIGH INPUTWIRING DIAGRAM
2014 Subaru Impreza Sport Limited

DTC P0103: Mass Or Volume Air Flow Circuit High Input: Wiring Diagram

2014 Subaru Impreza Sport LimitedSECTION Wiring Diagram

Engine electrical system < Ref. to ENGINE ELECTRICAL SYSTEM .>

Fig 1: Mass And Volume Air Flow - High Input - Circuit Diagram
G08315912Courtesy of SUBARU OF AMERICA, INC.
DTC PROCEDURE

Step Check Yes No
1 CHECK CURRENT DATA. 
  1. Start the engine.
  2. Read the value of «Air Flow Sensor Voltage » using Subaru Select Monitor.
    NOTE: For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". < Ref. to SUBARU SELECT MONITOR .>
 Is the value of «Air Flow Sensor Voltage» 5 V or more? Go to step 2  . Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.
NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2 CHECK HARNESS BETWEEN ECM AND MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connectors from the mass air flow and intake air temperature sensor.
  3. Start the engine.
  4. Read the value of «Air Flow Sensor Voltage » using Subaru Select Monitor.
    NOTE: For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". < Ref. to SUBARU SELECT MONITOR .>
 Is the value of «Air Flow Sensor Voltage» 5 V or more? Repair the short circuit of harness to power supply between ECM connector and the mass air flow and intake air temperature sensor connector. Go to step 3  .
3 CHECK HARNESS BETWEEN ECM AND MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Measure the resistance of harness between mass air flow and intake air temperature sensor connector and engine ground.

    Connector & terminal 

    (B3) No. 4 - Engine ground: 

 Is the resistance less than 5 Ω? Go to step 4  . Repair the harness and connector.
NOTE: In this case, repair the following item:
  • Open circuit in harness between ECM connector and the mass air flow and intake air temperature sensor connector
  • Poor contact of ECM connector
4 CHECK FOR POOR CONTACT. 
Check for poor contact of mass air flow and intake air temperature sensor connector.		 Is there poor contact of mass air flow and intake air temperature sensor connector? Repair the poor contact of mass air flow and intake air temperature sensor connector. Replace the mass air flow and intake air temperature sensor. < Ref. to MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR .>
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.