Nissan Altima L32. Instruction — part 263

P0101 MAF SENSOR

EC-173

< COMPONENT DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

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

Without CONSULT-III

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 and

ground.

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

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 4.

4.

CHECK MASS AIR FLOW SENSOR-III

With CONSULT-III

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-III and select “DATA MONITOR” mode.

5. Select “MAS A/F SE-B1” and check indication.

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

Without CONSULT-III

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.

Monitor item

Condition

MAS A/F SE-B1

MAS A/F SE-B1

Ignition switch ON (Engine stopped.)

Approx. 0.4 V

Idle (Engine is warmed-up to normal operating temperature.)

0.9 - 1.1 V

2,500 rpm (Engine is warmed-up to normal operating temperature.)

1.4 - 1.7 V

Idle to about 4,000 rpm

0.9 - 1.1 V to Approx. 2.4 V*

ECM

Ground

Condition

Voltage

Connector

Terminal

F13

58

(MAF

sensor
signal)

Ground

Ignition switch ON (Engine
stopped.)

Approx. 0.4 V

Idle (Engine is warmed-up to
normal operating tempera-
ture.)

0.9 - 1.1 V

2,500 rpm (Engine is
warmed-up to normal operat-
ing temperature.)

1.4 - 1.7 V

Idle to about 4,000 rpm

0.9 - 1.1 V to

Approx. 2.4 V*

PBIB3481E

Monitor item

Condition

MAS A/F SE-B1

MAS A/F SE-B1

Ignition switch ON (Engine stopped.)

Approx. 0.4 V

Idle (Engine is warmed-up to normal operating temperature.)

0.9 - 1.1 V

2,500 rpm (Engine is warmed-up to normal operating temperature.)

1.4 - 1.7 V

Idle to about 4,000 rpm

0.9 - 1.1 V to Approx. 2.4 V*

EC-174

< COMPONENT DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

P0101 MAF SENSOR

4. Check the voltage between ECM harness connector and

ground.

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

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Clean or replace mass air flow sensor.

ECM

Ground

Condition

Voltage

Connector

Terminal

F13

58

(MAF sen-
sor signal)

Ground

Ignition switch ON (Engine
stopped.)

Approx. 0.4 V

Idle (Engine is warmed-up
to normal operating tem-
perature.)

0.9 - 1.1 V

2,500 rpm (Engine is
warmed-up to normal oper-
ating temperature.)

1.4 - 1.7 V

Idle to about 4,000 rpm

0.9 - 1.1 V to

Approx. 2.4 V*

PBIB3481E

P0102, P0103 MAF SENSOR

EC-175

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[QR25DE FOR CALIFORNIA]

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P0102, P0103 MAF SENSOR

Description

INFOID:0000000004349217

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

INFOID:0000000004349218

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at

least 10 seconds before conducting the next test.
Which DTC is detected?

P0102 >> GO TO 2.

P0103 >> GO TO 3.

2.

PERFORM DTC CONFIRMATION PROCEDURE FOR DTC P0102

1. Start engine and wait at least 5 seconds.

2. Check DTC.
Is DTC detected?

YES

>> Go to

EC-176, "Diagnosis Procedure"

.

NO

>> INSPECTION END

3.

PERFORM DTC CONFIRMATION PROCEDURE FOR DTC P0103-I

1. Turn ignition switch ON and wait at least 5 seconds.

2. Check DTC.
Is DTC detected?

YES

>> Go to

EC-176, "Diagnosis Procedure"

.

NO

>> GO TO 4.

4.

PERFORM DTC CONFIRMATION PROCEDURE FOR DTC P0103-II

1. Start engine and wait at least 5 seconds.

2. Check DTC.
Is DTC detected?

YES

>> Go to

EC-176, "Diagnosis Procedure"

.

PBIA9559J

DTC No.

Trouble diagnosis

name

DTC detecting condition

Possible cause

P0102

Mass air flow sensor
circuit low input

An excessively low voltage from the sensor is sent
to ECM.

• Harness or connectors

(The sensor circuit is open or shorted.)

• Intake air leaks
• Mass air flow sensor

P0103

Mass air flow sensor
circuit high input

An excessively high voltage from the sensor is
sent to ECM.

• Harness or connectors

(The sensor circuit is open or shorted.)

• Mass air flow sensor

EC-176

< COMPONENT DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

P0102, P0103 MAF SENSOR

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000004349219

1.

INSPECTION START

Confirm the detected DTC.
Which DTC is detected?

P0102 >> GO TO 2.

P0103 >> GO TO 3.

2.

CHECK INTAKE SYSTEM

Check the following for connection.

• Air duct

• Vacuum hoses

• Intake air passage between air duct to intake manifold
Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Reconnect the parts.

3.

CHECK GROUND CONNECTION

1. Turn ignition switch OFF.

2. Check ground connection E9. Refer to Ground Inspection in

GI-45, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace ground connection.

4.

CHECK MAF SENSOR POWER SUPPLY CIRCUIT

1. Disconnect mass air flow (MAF) sensor harness connector.

2. Turn ignition switch ON.

3. Check the voltage between MAF sensor harness connector and

ground.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> GO TO 5.

5.

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.

6.

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.

MAF sensor

Ground

Voltage

Connector

Terminal

F31

5

Ground

Battery voltage

PBIB1169E