Infiniti F50. Manual - part 385

DTC P0102, P0103 MAF SENSOR

EC-181

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Wiring Diagram

EBS00LXP

TBWM0142E

EC-182

DTC P0102, P0103 MAF SENSOR

Specification data are reference values and are measured between each terminal and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

Diagnostic Procedure

EBS00LXQ

1. 

INSPECTION START

Which malfunction (P0102 or P0103) is duplicated?

P0102 or P0103

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 and intake manifold

OK or NG

OK

>> GO TO 3.

NG

>> Reconnect the parts.

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

42

W/B

ECM relay
(Self shut-off)

[Engine is running]
[Ignition switch “OFF”]

●

For a few seconds after turning ignition 
switch “OFF”

0 - 1.0V

[Ignition switch “OFF”]

●

More than a few seconds passed after turn-
ing ignition switch “OFF”

BATTERY VOLTAGE
(11 - 14V)

91

B/Y

Mass air flow sensor

[Engine is running]

●

Warm-up condition

●

Idle speed

1.1 - 1.5V

[Engine is running]

●

Warm-up condition

●

Engine speed is 2,500 rpm.

1.7 - 2.4V

103

L

Sensor power supply

[Ignition switch “ON”]

Approximately 5V

109

LG

Mass air flow sensor ground

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 0V

163
166

R
R

Power supply for ECM

[Ignition switch “ON”]

BATTERY VOLTAGE
(11 - 14V)

DTC P0102, P0103 MAF SENSOR

EC-183

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3. 

RETIGHTEN GROUND SCREWS

1.

Turn ignition switch “OFF”.

2.

Loosen and retighten engine ground screws.

>> GO TO 4.

4. 

CHECK MAF SENSOR POWER SUPPLY CIRCUIT

1.

Disconnect MAF sensor harness connector.

2.

Turn ignition switch “ON”.

3.

Check voltage between MAF sensor terminals 2, 4 and ground
with CONSULT-II or tester.

OK or NG

OK

>> GO TO 6.

NG

>> GO TO 5.

5. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors M135, F105

●

Harness for open or short between mass air flow sensor and ECM relay

●

Harness for open or short between mass air flow sensor and ECM

>> Repair harness or connectors.

PBIB0011E

PBIB0012E

Terminal

Voltage

2

Approximately 5V

4

Battery voltage

PBIB0076E

EC-184

DTC P0102, P0103 MAF SENSOR

6. 

CHECK MAF SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch “OFF”.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between MAF sensor terminal 3 and ECM terminal 109.
Refer to Wiring Diagram.

4.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 7.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

7. 

CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Check harness continuity between MAF sensor terminal 1 and ECM terminal 91.
Refer to Wiring Diagram.

2.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 8.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

8. 

CHECK MASS AIR FLOW SENSOR

Refer to 

EC-184, "Component Inspection"

 .

OK or NG

OK

>> GO TO 9.

NG

>> Replace mass air flow sensor.

9. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-132, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

EBS00LXR

MASS AIR FLOW SENSOR

1.

Reconnect harness connectors disconnected.

2.

Start engine and warm it up to normal operating temperature.

3.

Check voltage between ECM terminal 91 (Mass air flow sensor
signal) and ground.

*: Make sure linear voltage rises as engine speed increases to about 4,000 rpm.

4.

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.

Continuity should exist.

Continuity should exist.

Condition

Voltage V

Ignition switch “ON” (Engine stopped.)

Approx. 1.0

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

1.1 - 1.5

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

1.7 - 2.4

Idle to about 4,000 rpm*

1.1 - 1.5 to Approx. 4.0

PBIB0078E