Infiniti Q45. Manual - part 392

DTC P0102, P0103 MAF SENSOR

EC-207

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

NBS001ST

INSPECTION START

Which malfunction (P0102 or P0103) is duplicated?

P0102 or P0103

P0102 >> GO TO 2.
P0103 >> GO TO 3.

CHECK INTAKE SYSTEM

Check the following for connection.

●

Air duct

●

Vacuum hoses

●

Intake air passage between air duct and intake manifold

OK or NG

>> GO TO 3.

>> Reconnect the parts.

TER-

MINAL

NO.

WIRE

COLOR

ITEM

CONDITION

DATA (DC Voltage)

B/Y

Mass air flow sensor

[Engine is running]

●

Warm-up condition

●

Idle speed

1.0 - 1.2V

[Engine is running]

●

Warm-up condition

●

Engine speed: 2,500 rpm

1.6 - 1.9V

Sensor ground
(MAF sensor, IAT sensor,
ECT sensor, FTT sensor,
EVAP control system pres-
sure sensor, PSP sensor,
ICC steering switch, ASCD
steering switch, Refrigerant
pressure sensor)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 0V

111

W/B

ECM relay
(Self shut-off)

[Engine is running]
[Ignition switch: OFF]

●

For a few seconds after turning ignition
switch OFF

0 - 1.5V

[Ignition switch: OFF]

●

More than a few seconds after turning igni-
tion switch OFF

BATTERY VOLTAGE
(11 - 14V)

119

120

R
R

Power supply for ECM

[Ignition switch: ON]

BATTERY VOLTAGE
(11 - 14V)

EC-208

DTC P0102, P0103 MAF SENSOR

CHECK GROUND CONNECTIONS

Turn ignition switch OFF.

Loosen and retighten three ground screws on the body.
Refer to

EC-154, "Ground Inspection"

OK or NG

>> GO TO 4.

>> Repair or replace ground connections.

CHECK MAF SENSOR POWER SUPPLY CIRCUIT

Disconnect mass air flow (MAF) sensor harness connector.

Turn ignition switch ON.

Check voltage between MAF sensor terminal 2 and ground with
CONSULT-II or tester.

OK or NG

>> GO TO 6.

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

PBIB2417E

PBIB2418E

Voltage: Battery voltage

PBIB1168E

DTC P0102, P0103 MAF SENSOR

EC-209

CHECK MAF SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

Turn ignition switch OFF.

Disconnect ECM harness connector.

Check harness continuity between MAF sensor terminal 3 and ECM terminal 67.
Refer to Wiring Diagram.

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

OK or NG

>> GO TO 7.

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

CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

Check harness continuity between MAF sensor terminal 4 and ECM terminal 51.
Refer to Wiring Diagram.

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

OK or NG

>> GO TO 8.

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

CHECK MASS AIR FLOW SENSOR

Refer to

EC-209, "Component Inspection"

OK or NG

>> GO TO 9.

>> Replace mass air flow sensor.

CHECK INTERMITTENT INCIDENT

Refer to

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

>> INSPECTION END

Component Inspection

NBS001SU

MASS AIR FLOW SENSOR

With CONSULT-II

Reconnect all harness connectors disconnected.

Start engine and warm it up to normal operating temperature.

Connect CONSULT-II and select “DATA MONITOR” mode.

Select “MAS A/F SE-B1” and check indication under the follow-
ing conditions.

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

If the voltage is out of specification, proceed the following.

Continuity should exist.

Condition

MAS A/F SE-B1 (V)

Ignition switch ON (Engine stopped.)

Approx. 0.4

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

1.0 - 1.2

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

1.6 - 1.9

Idle to about 4,000 rpm

1.0 - 1.2 to Approx. 2.4*

PBIB2371E

EC-210

DTC P0102, P0103 MAF SENSOR

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

If NG, repair or replace malfunctioning part and perform step 2 to 4 again.
If OK, go to next step.

Turn ignition switch OFF.

Disconnect mass air flow sensor harness connector and reconnect it again.

Perform step 2 to 4 again.

If NG, clean or replace mass air flow sensor.

Without CONSULT-II

Reconnect all harness connectors disconnected.

Start engine and warm it up to normal operating temperature.

Check voltage between ECM terminal 51 (Mass air flow sensor
signal) and ground.

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

If the voltage is out of specification, proceed the following.

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

If NG, repair or replace malfunctioning part and perform step 2 to 3 again.
If OK, go to next step.

Turn ignition switch OFF.

Disconnect mass air flow sensor harness connector and reconnect it again.

Perform step 2 and 3 again.

If NG, clean or replace mass air flow sensor.

Removal and Installation

NBS001SV

MASS AIR FLOW SENSOR

Refer to

EM-17, "AIR CLEANER AND AIR DUCT"

Condition

Voltage V

Ignition switch ON (Engine stopped.)

Approx. 0.4

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

1.0 - 1.2

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

1.6 - 1.9

Idle to about 4,000 rpm

1.0 - 1.2 to Approx. 2.4*

PBIB1106E

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