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Code 3: Manifold Air Pressure Sensor

  1. Turn ignition off. Remove alternator sense fuse for 10 seconds to reset ECU. Start engine and check for PGM-FI light on or off. If light is off, test drive and check again.
  2. If light is on, turn ignition off. Connect inspection adapter between MAP sensor and right side wire harness. Turn ignition on. Measure voltage between Red terminal and Green terminal. If voltage is approximately 5 volts, go to step  5 .
  3. If voltage is not approximately 5 volt, measure voltage between Red terminal and body ground. If approximately 5 volt, repair open in Green/White wire between ECU (C14) and MAP sensor.
  4. If voltage is not within specification, turn ignition off. Connect system checker harness between ECU and connector. Measure voltage between C15 terminal and C14 terminal. If voltage is approximately 5 volts, repair open in Red/White wire between ECU (C15) and MAP sensor. If voltage is not within specification, substitute a known good ECU and recheck. If voltage is okay, replace original ECU.
  5. Measure voltage between White terminal and Green terminal. If there is not approximately 3 volts shown, replace MAP sensor and repair short in Blue wire between ECU (C11) and MAP sensor.
  6. If voltage is not a specified, turn ignition off. Connect system checker harness between ECU and connector. Turn ignition on. Measure voltage between C11 terminal and C14 terminal. If voltage is 3 volts, substitute a known good ECU and recheck. If symptom/indication disappears, replace original ECU. If measurement is not 3 volts, repair open in Blue wire between ECU (C11) and MAP sensor.
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