2007 INFINITI QX56 engine

DTC P0011, P0021 IVT CONTROL
EC-155
< SERVICE INFORMATION >
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: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000003531653
1.CHECK OIL PRESSURE WARNING LAMP
1. Start engine.
2. Check oil pressure warning lamp and confirm it is not illumi-
nated.
OK or NG
OK >> GO TO 2.
NG >> Go to LU-8, "
Inspection".
2.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
11 L GIntake valve timing control
solenoid valve (Bank 2)[Engine is running]
•Warm-up condition
• Idle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
•Warm-up condition
• Engine speed: 2,000rpm7 - 12V
53 LIntake valve timing control
position sensor (Bank 2)[Engine is running]
•Warm-up condition
• Idle speed0 - 1.0V
[Engine is running]
• Engine speed: 2,000 rpm0 - 1.0V
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)
PBIB1790E
PBIB2046E
PBIA8559J

EC-160
< SERVICE INFORMATION >
DTC P0011, P0021 IVT CONTROL
4. Visually check the sensor for chipping.
5. Check resistance as shown below.
6. If NG, replace intake valve timing control position sensor. Refer
to EC-160
.
INTAKE VALVE TIMING CONTROL SOLENOID VALVE
1. Disconnect intake valve timing control solenoid valve harness connector.
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-160
.
If OK, go to next step.
3. Remove intake valve timing control solenoid valve. Refer to EC-
160.
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.
NOTE:
Always replace O-ring when intake valve timing control
solenoid valve is removed.
Removal and InstallationINFOID:0000000003531655
INTAKE VALVE TIMING CONTROL POSITION SENSOR (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".
SEF362Z
Terminal No. (Polarity) Resistance Ω [at 25°C (77°F)]
3 (+) - 1 (-)
Except 0 or ∞ 2 (+) - 1 (-)
3 (+) - 2 (-)
PBIB0194E
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

DTC P0011, P0021 IVT CONTROL
EC-161
< SERVICE INFORMATION >
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3. Disconnect intake valve timing control position sensor (bank 2) connector.
4. Remove intake valve timing control position sensor (bank 2) (1)
from intake valve control solenoid cover (bank 2) (3).
Installation
Installation is in the reverse order of removal.
CAUTION:
Replace the O-ring (2) of the intake valve timing control position sensor with a new one, then lubricate
O-ring with engine oil before installing.
INTAKE VALVE TIMING CONTROL POSITION SENSOR (BANK 1)
Removal
1. Remove engine room cover using power tool. Refer to EM-12, "Removal and Installation".
2. Disconnect intake valve timing control position sensor (bank 1) connector.
3. Remove intake valve timing control position sensor (bank 1) (1)
from intake valve control solenoid cover (bank 1) (3).
Installation
Installation is in the reverse order of removal.
CAUTION:
Replace the O-ring (2) of the intake valve timing control position sensor with a new one, then lubricate
O-ring with engine oil before installing.
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.
LBIA0475E
Intake valve timing control position sensor bolt : 9.6 N·m (0.98 kg-m, 85 in-lb)
LBIA0476E
Intake valve timing control position sensor bolt : 9.6 N·m (0.98 kg-m, 85 in-lb)

EC-162
< SERVICE INFORMATION >
DTC P0011, P0021 IVT CONTROL
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".
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.
LBIA0477E
Intake valve timing control solenoid valve bolt : 9.6 N·m (0.98 kg-m, 85 in-lb)
LBIA0478E
Intake valve timing control solenoid valve bolt : 9.6 N·m (0.98 kg-m, 85 in-lb)

DTC P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-163
< SERVICE INFORMATION >
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DTC P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
DescriptionINFOID:0000000003531656
SYSTEM DESCRIPTION
The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating
condition to keep the temperature of A/F sensor 1 element at the specified range.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531657
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531658
DTC Confirmation ProcedureINFOID:0000000003531659
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is between 10.5V and 16V at
idle.
WITH CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Start engine and let it idle for at least 10 seconds.
3. If 1st trip DTC is detected, go to EC-167, "
Diagnosis Procedure".
Sensor Input Signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speed
Air fuel ratio (A/F) sensor 1
heater controlAir fuel ratio (A/F) sensor 1
heater
Mass air flow sensor Amount of intake air
MONITOR ITEM CONDITION SPECIFICATION
A/F S1 HTR (B1)
A/F S1 HTR (B2)• Engine: After warming up, idle the engine 4 - 100%
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0031
0031
(Bank 1)
Air fuel ratio (A/F) sensor
1 heater control circuit lowThe current amperage in the air fuel ratio (A/F) sen-
sor 1 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the air fuel ratio (A/F) sensor 1 heater.)• Harness or connectors
(The A/F sensor 1 heater circuit is
open or shorted.)
• A/F sensor 1 heater P0051
0051
(Bank 2)
P0032
0032
(Bank 1)Air fuel ratio (A/F) sensor
1 heater control circuit
highThe current amperage in the air fuel ratio (A/F) sen-
sor 1 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the air fuel ratio (A/F) sensor 1 heater.)• Harness or connectors
(The A/F sensor 1 heater circuit is
shorted.)
• A/F sensor 1 heater P0052
0052
(Bank 2)
SEF058Y

DTC P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-165
< SERVICE INFORMATION >
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Pulse signal is measured by CONSULT-II.
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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)TER-
MI-
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NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
2 LG/B A/F sensor 1 heater (bank 1)[Engine is running]
•Warm-up condition
• Idle speed
(More than 140 seconds after starting en-
gine)Approximately 2.9 - 8.8V
35 BR/R A/F sensor 1 (bank 1)[Engine is running]
•Warm-up condition
• Engine speed: 2,000 rpmApproximately 1.8V
Output voltage varies with air fuel
ratio.
56 BR/G A/F sensor 1 (bank 1)[Ignition switch: ON]Approximately 2.2V
PBIA8148J

DTC P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-167
< SERVICE INFORMATION >
C
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EC
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: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000003531661
1.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 2.
NG >> Repair or replace ground connections.
2.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect air fuel ratio (A/F) sensor 1 harness connector.
2. Turn ignition switch ON.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
16 G/L A/F sensor 1 (bank 2)[Engine is running]
•Warm-up condition
• Engine speed: 2,000 rpmApproximately 1.8V
Output voltage varies with air fuel
ratio.
24
43GR/G
GR/GA/F sensor 1 heater (bank 2)[Engine is running]
•Warm-up condition
• Idle speed
(More than 140 seconds after starting en-
gine)Approximately 2.9 - 8.8V
75 L/P A/F sensor 1 (bank 2)[Ignition switch: ON]Approximately 2.2V
PBIA8148J
BBIA0354E
BBIA0376E

EC-170
< SERVICE INFORMATION >
DTC P0037, P0038, P0057, P0058 HO2S2 HEATER
DTC P0037, P0038, P0057, P0058 HO2S2 HEATER
DescriptionINFOID:0000000003531664
SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the heated oxygen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
OPERATION
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531665
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531666
DTC Confirmation ProcedureINFOID:0000000003531667
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.
TESTING CONDITION:
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speed
Heated oxygen sensor 2
heater controlHeated oxygen sensor 2 heater
Engine coolant temperature sensor Engine coolant temperature
Mass air flow sensor Amount of intake air
Engine speed rpm Heated oxygen sensor 2 heater
Above 3,600OFF
Below 3,600 rpm after the following conditions are met.
• Engine: After warming up
• Keeping the engine speed between 3,500 and 4,000 rpm for 1
minute and at idle for 1 minute under no loadON
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 HTR (B1)
HO2S2 HTR (B2)• Engine speed: Below 3,600 rpm after the following conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and
at idle for 1 minute under no loadON
• Engine speed: Above 3,600 rpm OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0037
0037
(Bank 1)
Heated oxygen sensor 2
heater control circuit lowThe current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)• Harness or connectors
(The heated oxygen sensor 2 heater
circuit is open or shorted.)
• Heated oxygen sensor 2 heater P0057
0057
(Bank 2)
P0038
0038
(Bank 1)
Heated oxygen sensor 2
heater control circuit highThe current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)• Harness or connectors
(The heated oxygen sensor 2 heater
circuit is shorted.)
• Heated oxygen sensor 2 heater P0058
0058
(Bank 2)