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Home >> Nissan-Datsun >> 2009 >> Quest Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS U0101 To P0153 >> DTC P0112, P0113 IAT Sensor >> Diagnosis Procedure

Diagnosis Procedure

  1. CHECK GROUND CONNECTIONS
    1. Turn ignition switch OFF.
    2. Loosen and retighten three ground screws on the body. Refer to , "GROUND INSPECTION ".
    Fig 1: Identifying Body Ground E24, ECM And Body Ground E9
    G05931428Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace ground connections.

  2. CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
    1. Disconnect mass air flow sensor (intake air temperature sensor is built-into) harness connector.
    2. Turn ignition switch ON.
      Fig 2: Identifying Mass Air Flow Sensor And Air Cleaner
      G04905244Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between mass air flow sensor terminal 2 and ground.

    Voltage: Approximately 5 V 

    OK or NG 

    OK: GO TO 3.

    NG: Repair harness or connectors.

    Fig 3: Checking Voltage Between Mass Air Flow Sensor Terminal 2 And Ground
    G04905263Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK INTAKE AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between mass air flow sensor terminal 1 and ECM terminal 67.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

    4. Also check harness for short to ground and short to power.

    OK or NG 

    OK: GO TO 4.

    NG: Repair open circuit or short to ground or short to power in harness or connectors.

  4. CHECK INTAKE AIR TEMPERATURE SENSOR

    Refer to , "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 5.

    NG: Replace mass air flow sensor (with intake air temperature sensor).

  5. CHECK INTERMITTENT INCIDENT

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    INSPECTION END