Nissan Maxima Service and Repair Manual: P0101 MAF sensor

Description

The mass air flow sensor (1) is placed in the stream of intake air. It measures the intake flow rate by measuring a part of the entire intake flow. The mass air flow sensor controls the temperature of the hot wire to a certain amount. The heat generated by the hot wire is reduced as the intake air flows around it. The greater air flow, the greater the heat loss.

Therefore, the electric current supplied to hot wire is changed to maintain the temperature of the hot wire as air flow increases. The ECM detects the air flow by means of this current change.

DTC Logic

DTC DETECTION LOGIC

NOTE: If DTC P0101 is displayed with other DTC, first perform the trouble diagnosis for other DTC.

DTC CONFIRMATION PROCEDURE

1.PRECONDITIONING

If DTC CONFIRMATION PROCEDURE has been previously conducted, always perform the following procedure before conducting the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.

2.PERFORM DTC CONFIRMATION PROCEDURE

1. Start engine and warm it up to normal operating temperature.
2. Drive the vehicle for at least 5 seconds under the following conditions:

CAUTION: Always drive vehicle at safe speed.

NOTE:

•  The gear must be fixed while driving the vehicle.
•  Keep the accelerator pedal as steady as possible during cruising.

3. Check 1st trip DTC.

Diagnosis Procedure

1.CHECK INTAKE SYSTEM

Check the following for connection.

• Air duct
• Vacuum hoses
• Intake air passage between air duct and intake manifold

2.CHECK GROUND CONNECTION

1. Turn ignition switch OFF.
2. Check ground connection E9.

3.CHECK MASS AIR FLOW (MAF) SENSOR POWER SUPPLY CIRCUIT

1. Disconnect MAF sensor harness connector.
2. Turn ignition switch ON.
3. Check the voltage between MAF sensor harness connector and ground.

4.DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E11, F2
• Junction block connectors E44, E45
• Harness for open or short between mass air flow sensor and ECM
• Harness for open or short between mass air flow sensor and IPDM E/R

5.CHECK MAF SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between MAF sensor harness connector and ECM harness connector.
4. Also check harness for short to ground and short to power.

6.CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check the continuity between MAF sensor harness connector and ECM harness connector.
2. Also check harness for short to ground and short to power

7.CHECK INTAKE AIR TEMPERATURE SENSOR

Check intake air temperature sensor.

8.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

Check EVAP control system pressure sensor.

9.CHECK MAF SENSOR

Check MAF sensor

10.CHECK INTERMITTENT INCIDENT

Check intermittent incident

Component Inspection

1.CHECK MASS AIR FLOW SENSOR-I

With CONSULT

1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Connect CONSULT and select "DATA MONITOR" mode.
4. Select "MAS A/F SE-B1" and check indication under the following conditions.

*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.

1. Without CONSULT Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check the voltage between ECM harness connector terminals under the following conditions.

*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.

2.CHECK FOR THE CAUSE OF UNEVEN AIR FLOW VIA THE MASS AIR FLOW SENSOR

Check for the cause of uneven air flow via the mass air flow sensor. Refer to the following.

• Crushed air ducts
• Malfunctioning seal of air cleaner element
• Uneven dirt of air cleaner element
• Improper specification of intake air system parts

3.CHECK MASS AIR FLOW SENSOR-II

With CONSULT

1. Repair or replace malfunctioning part.
2. Start engine and warm it up to normal operating temperature.
3. Connect CONSULT and select "DATA MONITOR" mode.
4. Select "MAS A/F SE-B1" and check indication under the following conditions.

*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.

Without CONSULT

1. Repair or replace malfunctioning part.
2. Start engine and warm it up to normal operating temperature.
3. Check the voltage between ECM harness connector terminals under the following conditions

*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.

4.CHECK MASS AIR FLOW SENSOR-III

With CONSULT

1. Turn ignition switch OFF.
2. Disconnect mass air flow sensor harness connector and reconnect it again.
3. Start engine and warm it up to normal operating temperature.
4. Connect CONSULT and select "DATA MONITOR" mode.
5. Select "MAS A/F SE-B1" and check indication under the following conditions.

*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.

Without CONSULT

1. Turn ignition switch OFF.
2. Disconnect mass air flow sensor harness connector and reconnect it again.
3. Start engine and warm it up to normal operating temperature.
4. Check the voltage between ECM harness connector terminals under the following conditions.

*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm