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Infiniti QX56 (JA60). Manual - part 364

EC-108

< COMPONENT DIAGNOSIS >

[VK56DE]

P0101 MAF SENSOR

>> GO TO 11.

>> Replace mass air flow sensor.

11.

CHECK INTERMITTENT INCIDENT

Refer to

GI-35, "How to Check Terminal"

and

GI-38, "Intermittent Incident"

>> INSPECTION END

Component Inspection

INFOID:0000000005149115

MASS AIR FLOW SENSOR

With CONSULT-III

1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Connect CONSULT-III and select “DATA MONITOR” mode.
4. Select “MAS A/F SE-B1” and check indication under the following conditions.

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

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

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

If OK, go to next step.

6. Turn ignition switch OFF.
7. Disconnect mass air flow sensor harness connector and reconnect it again.
8. Perform step 2 to 4 again.
9. If NG, clean or replace mass air flow sensor.

Without CONSULT-III

1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. 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.

Condition

MAS A/F SE-B1 (V)

Ignition switch ON (Engine stopped.)

Approx. 0.4

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

0.9 - 1.3

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

1.7 - 2.1

Idle to about 4,000 rpm

0.9 - 1.3 to Approx. 2.4*

Condition

MAS A/F SE-B1 (V)

Ignition switch ON (Engine stopped.)

Approx. 0.4

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

0.9 - 1.3

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

1.7 - 2.1

Idle to about 4,000 rpm

0.9 - 1.3 to Approx. 2.4*

PBIB1106E

P0101 MAF SENSOR

EC-109

< COMPONENT DIAGNOSIS >

[VK56DE]

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

b. If NG, repair or replace malfunctioning part and perform step 2 and 3 again.

If OK, go to next step.

5. Turn ignition switch OFF.
6. Disconnect mass air flow sensor harness connector and reconnect it again.
7. Perform step 2 and 3 again.
8. If NG, clean or replace mass air flow sensor.

EC-110

< COMPONENT DIAGNOSIS >

[VK56DE]

P0102, P0103 MAF SENSOR

P0102, P0103 MAF SENSOR

Component Description

INFOID:0000000005149116

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 the 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.

On Board Diagnosis Logic

INFOID:0000000005149117

These self-diagnoses have the one trip detection logic.

FAIL-SAFE MODE

When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.

DTC Confirmation Procedure

INFOID:0000000005149118

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next step.
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.

PROCEDURE FOR DTC P0102

1. Start engine and wait at least 5 seconds.

2. Check DTC.

3. If DTC is detected, go to

EC-111, "Diagnosis Procedure"

PROCEDURE FOR DTC P0103

1. Turn ignition switch ON.

2. Wait at least 5 seconds.

3. Check DTC.

4. If DTC is detected, go to

EC-111, "Diagnosis Procedure"

If DTC is not detected, go to next step.

5. Start engine and wait at least 5 seconds.

6. Check DTC.

7. If DTC is detected, go to

EC-111, "Diagnosis Procedure"

BBIA0355E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0102
0102

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
0103

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

Detected items

Engine operating condition in fail-safe mode

Mass air flow sensor circuit

Engine speed will not rise more than 2,400 rpm due to the fuel cut.

P0102, P0103 MAF SENSOR

EC-111

< COMPONENT DIAGNOSIS >

[VK56DE]

Diagnosis Procedure

INFOID:0000000005149119

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 to intake manifold
OK or NG

>> GO TO 3.

>> Reconnect the parts.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten three ground screws on the body.

Refer to

EC-85, "Ground Inspection"

OK or NG

>> GO TO 4.

>> Repair or replace ground connections.

CHECK MAF SENSOR POWER SUPPLY CIRCUIT

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

2. Turn ignition switch ON.

BBIA0354E

BBIA0368E

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