Mass air flow sensor

Good evening,

I want to be sure we are talking about the same thing.

A mass air flow sensor does not have a vacuum line. Can you post a picture of the sensor you have?

There is a TSB for the 101 and I posted it below. Is this the bulletin you have?

Roy

RELATED VEHICLES: 2011-2012 Altima 2.5L, 3.5L; Cube 1.8L; Frontier 4.0L; Maxima 3.5L; Pathfinder 4.0L, 5.6L; Sentra 2.0L; Xterra 4.0L

SUMMARY: P0101-MAF Sensor Circuit Range/Performance Problem; 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 more air, 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.

RELATED TSB: 12-051F

PROBABLE CAUSES:

Engine Control Module (ECM) (Re-Flash)
Mass Air-flow (MAF) Sensor
Air Induction Leaks
EVAP Control System Pressure Sensor
Intake Air Temperature Sensor
Wiring or Connectors
RELATED COMMUNITY CASES:

Lack of Power
No Power Under Acceleration
No Power Under Acceleration
Engine Intermittently Cuts Out
DIAGNOSIS:

HINT: If other DTCs are displayed with P0101, diagnose and repair those first.

1. Check the referenced TSB, step 6, to see if the vehicle you have is included in the procedure. If not, proceed with normal troubleshooting.

2. Start the engine and warm to operating temperature and check for any vacuum leaks in the air induction system after the MAF sensor. Remedy as necessary.

3. With a capable scan tool monitor the MAF sensor and look for the following values:

Output voltage at idle: 0.8 to 1.2
Grams/second at idle: 1.0 to 4.0
Grams/second at 2500 RPMs: 4.0 to 10
4. With a DVOM at terminal 58 (MAF signal) of the ECM, check the voltage values at the given conditions in the following table.

If any of the above testing is not within specifications, replace the MAF sensor, clear codes and recheck.

YouTube - How to Know if a Mass Air Flow Sensor Is Bad
YouTube - OBD II Codes P0100, P0101, P0102, P0103, P0104 MAF Sensor

Hi and thanks for using 2CarPros.

Since you already reprogrammed the computer per the technical service bulletin, I need you to go through an extensive diagnostic procedure. Follow the procedure listed here. The attached pictures correlate with these directions.

I realize these are extensive, but if the reprogram didn't help, the problem is something different.

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P0101 MAF SENSOR

Description

Pic 1

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 more air, 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.

Pic 2

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.
- GO TO 2.

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.

Pic 3

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.
Is 1st trip DTC detected?
YES- Proceed to "Diagnosis Procedure".
NO- INSPECTION END

Diagnosis Procedure

1. CHECK INTAKE SYSTEM

Check the following for connection.

- Air duct
- Vacuum hoses
- Intake air passage between air duct and intake manifold
Is the inspection result normal?
YES- GO TO 2.
NO- Reconnect the parts.

2. CHECK GROUND CONNECTION

1. Turn ignition switch OFF.
2. Check ground connection E9. Refer to Ground Inspection in See: Vehicle > Initial Inspection and Diagnostic Overview > Circuit Inspection.
Is the inspection result normal?
YES- GO TO 3.
NO- Repair or replace ground connection.

3. CHECK MAF SENSOR POWER SUPPLY CIRCUIT

1. Disconnect mass air flow (MAF) sensor harness connector.
2. Turn ignition switch ON.

Pic 4

3. Check the voltage between MAF sensor harness connector and ground.

Pic 5

Is the inspection result normal?
YES- GO TO 5.
NO- GO TO 4.

4. DETECT MALFUNCTIONING PART

Check the following.
- Junction block connector E44
- Harness connector E11, F2
- 15A fuse (No.42)
- 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
- Repair open circuit or short to ground or short to power in harness or connectors.

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.

Pic 6

4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES- GO TO 6.
NO- Repair open circuit or short to ground or short to power in harness or connectors.

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

1. Check the continuity between MAF sensor harness connector and ECM harness connector.

Pic 7

2. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES- GO TO 7.
NO- Repair open circuit or short to ground or short to power in harness or connectors.

7. CHECK INTAKE AIR TEMPERATURE SENSOR

Check intake air temperature sensor.
See: A L L Diagnostic Trouble Codes ( DTC ) > P Code Charts > IAT Sensor For USA And Canada.
Is the inspection result normal?
YES- GO TO 8.
NO- Replace mass air flow sensor (with intake air temperature sensor). See: Air Cleaner Housing > Removal and Replacement > Removal And Installation.

8. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

See: A L L Diagnostic Trouble Codes ( DTC ) > P Code Charts > EVAP Control System Pressure Sensor For USA And Canada.
Is the inspection result normal?
YES- GO TO 9.
NO- Replace EVAP control system pressure sensor. See: Evaporative Vapor Pressure Sensor > Removal and Replacement > Removal And Installation.

9. CHECK MASS AIR FLOW SENSOR

Refer to "Component Inspection".
Is the inspection result normal?
YES- GO TO 10.
NO- Replace mass air flow sensor. See: Air Cleaner Housing > Removal and Replacement > Removal And Installation.

10. CHECK INTERMITTENT INCIDENT

See: Vehicle > Initial Inspection and Diagnostic Overview > Intermittent Incident.
- INSPECTION END

Component Inspection

1. CHECK MASS AIR FLOW SENSOR-I

With CONSULT
1. Turn ignition switch OFF.
2. Reconnect all harness connectors disconnected.
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.

Pic 8

Without CONSULT
1. Turn ignition switch OFF.
2. Reconnect all harness connectors disconnected.
3. Start engine and warm it up to normal operating temperature.

Pic 9

4. Check the voltage between ECM harness connector and ground.

Pic 10

Is the inspection result normal?
YES- GO TO 4.
NO- GO TO 2.

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

1. Turn ignition switch OFF.
2. Check for the cause of uneven air flow through mass air flow sensor. Refer to following.
-Crushed air ducts
-Malfunctioning seal of air cleaner element
-Uneven dirt of air cleaner element
-Improper specification of intake air system parts
Is the inspection result normal?
YES- GO TO 4.
NO- GO TO 3.

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.

Pic 11

Without CONSULT
1. Repair or replace malfunctioning part.
2. Start engine and warm it up to normal operating temperature.

Pic 12

3. Check the voltage between ECM harness connector and ground.

Pic 13

Is the inspection result normal?
YES- INSPECTION END
NO- GO TO 4.

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.

Pic 14

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.

Pic 15

4. Check the voltage between ECM harness connector and ground.

Pic 16

Is the inspection result normal?
YES- INSPECTION END
NO- Clean or replace mass air flow sensor. See: Air Cleaner Housing > Removal and Replacement > Removal And Installation.

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Let me know if this helps or if you have other questions.

Take care,
Joe

You are more than welcome to start a new question and we would be glad to help you.

Roy