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Home >> Subaru >> 2020 >> BRZ Limited, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostics) (1 Of 3) >> EFI System (FA20) >> DTC P0107: Manifold Absolute Pressure/Barometric Pressure Circuit Low Input; DTC P0108: Manifold Absolute Pressure/Barometric Pressure Circuit High Input >> Description of functions >> Inspection steps
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Inspection steps

NOTE: Read the freeze frame data using the SSM4. 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 of SSM4 data
    1. Connect the SSM4 to the DLC3.
    2. Turn the ignition switch to ON with engine stopped.
    3. Turn on the SSM4.
    4. Select the following menu items using the SSM4.: [Each System] / [Engine Control System] / [Data monitor] / [Mani. Absolute Pressure]
    5. Read [Mani. Absolute Pressure].

      Criteria: Indicates a value almost equal to the actual barometric pressure.

    Manifold absolute pressure reference

    Inspection conditions [Mani. Absolute Pressure]
    IG ON, engine stop 80 to 110 kPa
    NOTE: Normal barometric pressure is 101 kPa {758 mmHg}. As altitude increases 100 m {328 ft}, the atmospheric pressure decreases 1 kPa. This rate of change depends on the weather.

    Result

    Result Go to
    Malfunction A
    Normal B

    B: Inspection for problems that do not normally occur (Refer to INSPECTION FOR PROBLEMS THAT DO NOT NORMALLY OCCUR )

    A: Go to next step

  2. Check wiring harness and connector (air pressure sensor ASSY power supply voltage check)
    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 air pressure sensor ASSY.
    2. Measure the voltage between the terminals.

    Voltage

    Inspection terminals Inspection conditions Standard value
    C18-3(VC)- C18-1(E2) IG ON 4.5 to 5.5 V
    C18-2 (PIM) - C18-1 (E2) IG ON 4.0 to 5.0 V
    G12586162Courtesy of SUBARU OF AMERICA, INC.

    NG: Go to step  5.

    OK: Go to next step

  3. Replacement of air pressure sensor ASSY
    1. Replace the air pressure sensor ASSY. (Refer to REMOVAL )

    Next

    4 Clear DTC

    1. Connect the SSM4 to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn on the SSM4.
    4. Follow the SSM4 on-screen instructions to clear the DTCs. (Refer to CHECKING/CLEARING DTC )

    Next

  4. Perform test drive for operation check
    1. Perform test drive. (Refer to "TEST DRIVE " under "Description of functions")
    2. Connect the SSM4 to the DLC3.
    3. Turn the ignition switch to ON.
    4. Turn on the SSM4.
    5. Follow the SSM4 on-screen instructions to check the DTCs. (Refer to CHECKING/CLEARING DTC )

    Result

    Result Go to
    P0107 or P0108 is output. A
    No DTC is output B

    B: Complete

    A: Go to next step

    Replacement of the engine control computer (Refer to REMOVAL )

  5. Check wiring harness and connector (air pressure sensor ASSY - engine control computer)
    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 air pressure sensor ASSY.
    2. Disconnect the connector for the engine control computer.
    3. Measure the resistance between the terminals. (For terminal arrangement, refer to ECM TERMINAL ARRANGEMENT .)

    Resistance (open circuit check)

    Inspection terminals Inspection conditions Standard value
    A36-19 (VC) - C18-3 (VC) Always Less than 1 Ω
    A34-20 (PIM) - C18-2 (PIM) Always Less than 1 Ω
    A36-29 (E1) - C18-1 (E2) Always Less than 1 Ω

    Resistance (short circuit check)

    Inspection terminals Inspection conditions Standard value
    A36-19 (VC) and C18-3 (VC) - other terminals and chassis ground Always 10 k Ω or more
    A34-20 (PIM) and C18-2 (PIM) - other terminals and chassis ground Always 10 k Ω or more
    A36-29 (E1) and C18-1 (E2) - other terminals and chassis ground Always 10 k Ω or more

    NG: Repair or replacement of wiring harness or connector

    OK: Go to next step

    Replacement of the engine control computer (Refer to REMOVAL )