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Home >> Nissan-Datsun >> 2004 >> Altima Base, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control System - 2.5L >> DTC P0101: Map Sensor >> Component Inspection >> Mass Air Flow Sensor
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Mass Air Flow Sensor

  1. Reconnect harness connectors disconnected.
  2. Start engine and warm it up to normal operating temperature.
  3. Check voltage between ECM terminal 51 (Mass air flow sensor signal) and ground.
    CONDITIONS AND VOLTAGE

    Conditions Voltage V
    Ignition switch: ON (Engine stopped.) Less than 1.0
    Idle (Engine is warmed-up to normal operating temperature.) 0.8 - 1.3
    2, 500 RPM (Engine is warmed-up to normal operating temperature.) 1.5 - 2.1
    Idle to about 4, 000 RPM(1) 0.8 - 1.3 to Approx. 2.2
    (1) Make sure liner voltage rises as engine speed increases to about 4, 000 RPM.
  4. If the voltage is out of specification, proceed the following.
    • Turn ignition switch OFF.
    • Disconnect mass air flow sensor harness connector and reconnect it again.
      Fig 1: Checking Intermittent Incident
      G02884249Courtesy of NISSAN MOTOR CO., U.S.A.
    • Perform step 2 and 3 again.
  5. If NG, remove mass air flow sensor from air duct. Check hot wire for damage or dust.
  6. If NG, clean or replace mass air flow sensor.