Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSNISSAN-DATSUN2004ALTIMA S, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCEENGINE CONTROL SYSTEM - 2.5LDTC P0101: MAP SENSORCOMPONENT INSPECTIONMASS AIR FLOW SENSOR

2004 Nissan-Datsun Altima S, Automatic

Mass Air Flow Sensor

2004 Nissan-Datsun Altima S, AutomaticSECTION Mass Air Flow Sensor

Reconnect harness connectors disconnected.
Start engine and warm it up to normal operating temperature.

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.

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
  Courtesy of NISSAN MOTOR CO., U.S.A.
- Perform step 2 and 3 again.
If NG, remove mass air flow sensor from air duct. Check hot wire for damage or dust.
If NG, clean or replace mass air flow sensor.

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.