engine INFINITI QX56 2007 Factory Service Manual

EC-184
< SERVICE INFORMATION >
DTC P0075, P0081 IVT CONTROL SOLENOID VALVE
2. Check resistance between intake valve timing control solenoid
valve terminals as follows.
If NG, replace intake valve timing control solenoid valve. Refer to
EC-184
.
If OK, go to next step.
3. Remove intake valve timing control solenoid valve. Refer to EC-
184.
4. Provide 12V DC between intake valve timing control solenoid
valve terminals and then interrupt it. Make sure that the plunger
moves as shown in the figure.
CAUTION:
Do not apply 12V DC continuously for 5 seconds or more.
Doing so may result in damage to the coil in intake valve
timing control solenoid valve.
If NG, replace intake valve timing control solenoid valve. Refer to
EC-184
.
NOTE:
Always replace O-ring when intake valve timing control
solenoid valve is removed.
Removal and InstallationINFOID:0000000003531679
INTAKE VALVE TIMING CONTROL SOLENOID VALVE (BANK 2)
Removal
1. Remove engine room cover using power tool. Refer to EM-12, "Removal and Installation".
2. Remove air duct and resonator assembly. Refer to EM-15, "
Removal and Installation".
3. Remove drive belt. Refer to EM-13, "
Removal and Installation".
4. Disconnect intake valve timing control solenoid valve (bank 2) connector.
5. Remove intake valve timing control solenoid valve (bank 2) (2)
from intake valve control solenoid cover (bank 2) (1).
Installation
Installation is in the reverse order of removal.
CAUTION:
Replace the O-ring (3) of the intake valve timing control solenoid valve with a new one, then lubricate
O-ring with engine oil before installing.
INTAKE VALVE TIMING CONTROL SOLENOID VALVE (BANK 1)
Removal
1. Remove drive belt. Refer to EM-13, "Removal and Installation".
Terminals Resistance
1 and 2 7.0 - 7.5Ω [at 20°C (68°F)]
1 or 2 and ground∞Ω
(Continuity should not exist)
PBIB0193E
PBIB2275E
LBIA0477E
Intake valve timing control solenoid valve bolt : 9.6 N·m (0.98 kg-m, 85 in-lb)

DTC P0075, P0081 IVT CONTROL SOLENOID VALVE
EC-185
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
2. Disconnect intake valve timing control solenoid valve (bank 1) connector.
3. Remove intake valve timing control solenoid valve (bank 1) (3)
from intake valve control solenoid cover (bank 1) (1).
Installation
Installation is in the reverse order of removal.
CAUTION:
Replace the O-ring (2) of the intake valve timing control solenoid valve with a new one, then lubricate
O-ring with engine oil before installing.
LBIA0478E
Intake valve timing control solenoid valve bolt : 9.6 N·m (0.98 kg-m, 85 in-lb)

EC-186
< SERVICE INFORMATION >
DTC P0101 MAF SENSOR
DTC P0101 MAF SENSOR
Component DescriptionINFOID:0000000003531680
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.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531681
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531682
DTC Confirmation ProcedureINFOID:0000000003531683
Perform PROCEDURE FOR MALFUNCTION A first.
If the 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:
BBIA0355E
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE-B1 See EC-129
.
CAL/LD VALUE• Engine: After warming up
• Air conditioner switch: OFF
• Selector lever: P or N
•No loadIdle 14% - 33%
2,500 rpm 12% - 25%
MASS AIRFLOW• Engine: After warming up
• Air conditioner switch: OFF
• Selector lever: P or N
•No loadIdle 3.0 - 9.0 g·m/s
2,500 rpm 9.0 - 28.0 g·m/s
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0101
0101Mass air flow sensor circuit
range/performanceA)A high voltage from the sensor is sent to ECM
under light load driving condition.• Harness or connectors
(The sensor circuit is open or
shorted.)
• Mass air flow sensor
• EVAP control system pressure
sensor
• Intake air temperature sensor
B)A low voltage from the sensor is sent to ECM
under heavy load driving condition.• Harness or connectors
(The sensor circuit is open or
shorted.)
• Intake air leaks
• Mass air flow sensor
• EVAP control system pressure
sensor
• Intake air temperature sensor

DTC P0101 MAF SENSOR
EC-187
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
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-190, "
Diagnosis Procedure".
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-190, "
Diagnosis 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-190, "
Diagnosis Procedure".
If OK, go to following step.
SEF174Y
SEF243Y

EC-188
< SERVICE INFORMATION >
DTC P0101 MAF SENSOR
7. Maintain the following conditions for at least 10 consecutive sec-
onds.
8. If 1st trip DTC is detected, go to EC-190, "
Diagnosis Procedure".
Overall Function CheckINFOID:0000000003531684
PROCEDURE FOR MALFUNCTION B
Use this procedure to check the overall function of the mass air flow sensor circuit. During this check, a 1st trip
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-190, "
Diagnosis 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 locationDriving vehicle uphill (Increased engine load) will help
maintain the driving conditions required for this test.
PBIB0199E
SEF534P

EC-190
< SERVICE INFORMATION >
DTC P0101 MAF SENSOR
Diagnosis Procedure
INFOID:0000000003531686
1.INSPECTION START
Which malfunction (A or B) is duplicated?
A or B
A>>GO TO 3.
B>>GO TO 2.
2.CHECK INTAKE SYSTEM
Check the following for connection.
• Air duct
• Vacuum hoses
• Intake air passage between air duct to intake manifold
OK or NG
OK >> GO TO 3.
NG >> Reconnect the parts.
3.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-143, "
Ground Inspection".
OK or NG
OK >> GO TO 4.
NG >> Repair or replace ground connections.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
51 W Mass air flow sensor[Engine is running]
•Warm-up condition
• Idle speed1.0 - 1.3V
[Engine is running]
•Warm-up condition
• Engine speed: 2,500 rpm.1.7 - 2.1V
67 B Sensor ground[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
111 W / BECM relay
(Self shut-off)[Engine is running]
[Ignition switch: OFF]
• For a few seconds after turning ignition
switch OFF0 - 1.5V
[Ignition switch: OFF]
• More than a few seconds after turning igni-
tion switch OFFBATTERY VOLTAGE
(11 - 14V)
11 9
120BR
BRPower supply for ECM[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
BBIA0354E

EC-192
< SERVICE INFORMATION >
DTC P0101 MAF SENSOR
Refer to EC-204, "Component Inspection".
OK or NG
OK >> GO TO 9.
NG >> Replace intake air temperature sensor.
9.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
Refer to EC-394, "
Component Inspection".
OK or NG
OK >> GO TO 10.
NG >> Replace EVAP control system pressure sensor.
10.CHECK MASS AIR FLOW SENSOR
Refer to EC-192, "
Component Inspection".
OK or NG
OK >> GO TO 11.
NG >> Replace mass air flow sensor.
11 .CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Component InspectionINFOID:0000000003531687
MASS AIR FLOW SENSOR
With CONSULT-II
1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Connect CONSULT-II and select “DATA MONITOR” mode.
4. 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.
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-II
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 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.)1.7 - 2.1
Idle to about 4,000 rpm 1.0 - 1.3 to Approx. 2.4*
PBIB2371E

DTC P0101 MAF SENSOR
EC-193
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
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.
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.
Removal and InstallationINFOID:0000000003531688
MASS AIR FLOW SENSOR
Refer to EM-15.
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 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.)1.7 - 2.1
Idle to about 4,000 rpm 1.0 - 1.3 to Approx. 2.4*
PBIB1106E

EC-194
< SERVICE INFORMATION >
DTC P0102, P0103 MAF SENSOR
DTC P0102, P0103 MAF SENSOR
Component DescriptionINFOID:0000000003531689
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.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531690
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531691
These self-diagnoses have the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003531692
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 DTC P0102
With CONSULT-II
1. Turn ignition switch ON.
BBIA0355E
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE-B1 See EC-129
.
CAL/LD VALUE• Engine: After warming up
• Air conditioner switch: OFF
• Selector lever: P or N
•No loadIdle 14% - 33%
2,500 rpm 12% - 25%
MASS AIRFLOW• Engine: After warming up
• Air conditioner switch: OFF
• Selector lever: P or N
•No loadIdle 3.0 - 9.0 g·m/s
2,500 rpm 9.0 - 28.0 g·m/s
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0102
0102Mass air flow sensor circuit
low inputAn 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
0103Mass air flow sensor circuit
high inputAn 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.

DTC P0102, P0103 MAF SENSOR
EC-195
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and wait at least 5 seconds.
4. If DTC is detected, go to EC-197, "
Diagnosis Procedure".
With GST
Follow the procedure “With CONSULT-II” above.
PROCEDURE FOR DTC P0103
With CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 5 seconds.
4. If DTC is detected, go to EC-197, "
Diagnosis Procedure".
If DTC is not detected, go to next step.
5. Start engine and wait at least 5 seconds.
6. If DTC is detected, go to EC-197, "
Diagnosis Procedure".
With GST
Follow the procedure “With CONSULT-II” above.
SEF058Y
SEF058Y