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Home >> Subaru >> 2014 >> BRZ Limited, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostics) (1 Of 4) >> DTC P0112 Intake Air Temperature Circuit Low Input; DTC P0113 Intake Air Temperature Circuit High Input >> Description of functions >> Inspection steps
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Inspection steps

NOTE: Read the freeze frame data using the SSM3. A part of the engine running conditions under which the engine trouble occurred is recorded in the freeze frame data, which is useful for troubleshooting.
  1. Reading SSM3 data ([Intake Air Temp.])
    1. Connect the SSM3 to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn on the SSM3.
    4. Select the following menu items using the SSM3: [BRZ Check] / [Each System Check] / [Engine Control System] / [Current Data Display & Save] / [Intake Air Temp.]
    5. Read [Intake Air Temp.].
      RESULT

      Result Go to
      -40°C {-40°F} A
      120°C {248°F} B
      Equal to ambient temperature C
      NOTE:
      • If the SSM3 display is -40°C {-40°F}, there is an open circuit.
      • If the SSM3 display is 120°C {248°F}, there is a short circuit.

      B: Go to Step  4.

      C: Inspection for problems that do not normally occur (Refer to CHECK PROBLEMS THAT DO NOT CONSTANTLY OCCUR )

      A: Go to Next Step

  2. Reading SSM3 data (wiring harness open circuit check)

    SST 09843-18040

    1. Connect the SSM3 to the DLC3.
    2. Disconnect the connector of the intake air flow meter sub-assembly.
    3. Using SST (diagnostic check wire No. 2), short-circuit between terminals 1 and 2 of the intake air flow meter sub-assembly.
    4. Turn the ignition switch to ON.
    5. Select the following menu items using the SSM3: [BRZ Check] / [Each System Check] / [Engine Control System] / [Current Data Display & Save] / [Intake Air Temp.]
    6. Read [Current Data Display & Save].

      Standard value: 120°C {248°F}

      NG: Go to Step 3.

      Fig 1: Identifying Intake Air Flow Meter sub-assembly Connector Terminals
      G08553729Courtesy of SUBARU OF AMERICA, INC.

      OK: Replacement of intake air flow meter sub-assembly (Refer to INTAKE AIR FLOW METER S/A (FA20) )

  3. Check wiring harness and connector (engine control computer - intake air flow meter sub-assembly)
    NOTE: For the inspection procedure and precautions for wiring harnesses and connectors, refer to INSPECTION PROCEDURES FOR ELECTRICAL CIRCUITS AND HOW TO PERFORM .
    1. Disconnect the connector for the engine control computer.
    2. Disconnect the connector of the intake air flow meter sub-assembly.
    3. Measure the resistance between the terminals. (Refer to ECM TERMINAL ARRANGEMENT for the terminal arrangement)
      RESISTANCE (OPEN CIRCUIT CHECK)

      Inspection terminals Inspection conditions Standard value
      A33-12 (THA) - C16-1 (THA) Always Less than 1 Ω
      A36-29 (E1) - C16-2 (E2) Always Less than 1 Ω

      NG: Repair or replacement of wiring harness or connector

      OK: Replacement of the engine control computer (Refer to REMOVAL )

  4. Reading SSM3 data (wiring harness short circuit check)
    1. Disconnect the connector of the intake air flow meter sub-assembly.
    2. Connect the SSM3 to the DLC3.
    3. Turn the ignition switch to ON.
    4. Select the following menu items using the SSM3: [BRZ Check] / [Each System Check] / [Engine Control System] / [Current Data Display & Save] / [Intake Air Temp.]
    5. Read [Current Data Display & Save].

      Standard value: -40°C {-40°F}

      Fig 2: Intake Air Flow Meter sub-assembly And Engine Control Computer - Circuit Diagram
      G08553730Courtesy of SUBARU OF AMERICA, INC.

      NG: Go to Step 5.

      OK: Replacement of intake air flow meter sub-assembly (Refer to INTAKE AIR FLOW METER S/A (FA20) )

  5. Check wiring harness and connector (engine control computer - intake air flow meter sub-assembly)
    NOTE: For the inspection procedure and precautions for wiring harnesses and connectors, refer to INSPECTION PROCEDURES FOR ELECTRICAL CIRCUITS AND HOW TO PERFORM .
    1. Disconnect the connector for the engine control computer.
    2. Disconnect the connector of the intake air flow meter sub-assembly.
    3. Measure the resistance between the terminals. (Refer to ECM TERMINAL ARRANGEMENT for the terminal arrangement)
      RESISTANCE (SHORT CIRCUIT CHECK)

      Inspection terminals Inspection conditions Standard value
      A33-12 (THA) and C16-1 (THA) - other terminals and chassis ground Always 10 k Ωor more
      A36-29 (E1) and C16-2 (E2) - other terminals and chassis ground Always 10 k Ωor more

      NG: Repair or replacement of wiring harness or connector

      OK: Replacement of the engine control computer (Refer to REMOVAL )