Infiniti Q45. Manual - part 389

DTC P0101 MAF SENSOR

EC-195

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EC

DTC P0101 MAF SENSOR

PFP:22680

Component Description

NBS001SF

The mass air flow sensor is placed in the stream of intake air. It mea-
sures 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.

CONSULT-II Reference Value in Data Monitor Mode

NBS001SG

Specification data are reference values.

On Board Diagnosis Logic

NBS001SH

PBIB1604E

MONITOR ITEM

CONDITION

SPECIFICATION

MAS A/F SE-B1

See 

EC-135, "TROUBLE DIAGNOSIS - SPECIFICATION VALUE"

  .

CAL/LD VALUE

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Engine: After warming up

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Selector lever: P or N

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Air conditioner switch: OFF

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No load

Idle

15% - 35%

2,500 rpm

10% - 35%

MASS AIRFLOW

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Engine: After warming up

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Selector lever: P or N

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Air conditioner switch: OFF

●

No load

Idle

3.8 - 5.2 g·m/s

2,500 rpm

16.0 - 21.5 g·m/s

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0101
0101

Mass air flow sensor cir-
cuit range/performance

A)

A high voltage from the sensor is sent to ECM 
under light load driving condition.

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Harness or connectors
(The sensor circuit is open or 
shorted.)

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Mass air flow sensor

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EVAP control system pressure 
sensor

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Intake air temperature sensor

B)

A low voltage from the sensor is sent to ECM 
under heavy load driving condition.

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Harness or connectors
(The sensor circuit is open or 
shorted.)

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Intake air leaks

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Mass air flow sensor

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EVAP control system pressure 
sensor

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Intake air temperature sensor

EC-196

DTC P0101 MAF SENSOR

DTC Confirmation Procedure

NBS001SI

Perform PROCEDURE FOR MALFUNCTION A first.
If DTC cannot be confirmed, perform PROCEDURE FOR MALFUNCTION B.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

PROCEDURE FOR MALFUNCTION A

NOTE:
If engine will not start or stops soon, wait at least 10 seconds with engine stopped (Ignition switch ON) instead
of running engine at idle speed.

 With CONSULT-II

1.

Turn ignition switch ON.

2.

Select “DATA MONITOR” mode with CONSULT-II.

3.

Start engine and warm it up to normal operating temperature.

4.

Run engine for at least 10 seconds at idle speed.

5.

If 1st trip DTC is detected, go to 

EC-199, "Diagnostic Procedure"

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 With GST

Follow the procedure With CONSULT-II above.

PROCEDURE FOR MALFUNCTION B

CAUTION:

Always drive vehicle at a safe speed.

 With CONSULT-II 

1.

Turn ignition switch ON.

2.

Start engine and warm it up to normal operating temperature.
If engine cannot be started, go to 

EC-199, "Diagnostic Procedure"

 .

3.

Select “DATA MONITOR” mode with CONSULT-II.

4.

Check the voltage of “MAS A/F SE-B1” with “DATA MONITOR”.

5.

Increases engine speed to about 4,000 rpm.

6.

Monitor the linear voltage rise in response to engine speed
increases.
If NG, go to 

EC-199, "Diagnostic Procedure"

 .

If OK, go to following step.

SEF174Y

SEF243Y

DTC P0101 MAF SENSOR

EC-197

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7.

Maintain the following conditions for at least 10 consecutive sec-
onds.

8.

If 1st trip DTC is detected, go to 

EC-199, "Diagnostic Procedure"

.

Overall Function Check

NBS001SJ

PROCEDURE FOR MALFUNCTION B

Use this procedure to check the overall function of the mass air flow sensor circuit. During this check, a DTC
might not be confirmed.

 With GST

1.

Start engine and warm it up to normal operating temperature.

2.

Select “Service $01” with GST.

3.

Check the mass air flow sensor signal with “Service $01”.

4.

Check for linear mass air flow sensor signal value rise in
response to increases to about 4,000 rpm in engine speed.

5.

If NG, go to 

EC-199, "Diagnostic Procedure"

 .

ENG SPEED

More than 2,000 rpm

THRTL SEN 1

More than 3V

THRTL SEN 2

More than 3V

Selector lever

Suitable position

Driving location

Driving vehicle uphill (Increased engine load) will help 
maintain the driving conditions required for this test.

PBIB0199E

SEF534P

EC-198

DTC P0101 MAF SENSOR

Wiring Diagram

NBS001SK

TBWM1223E