2001 INFINITI QX4 Engine control

SEF359Z
Component DescriptionNBEC0705Intake valve advance unit position sensors are located in the front
cylinder heads in both right/left banks.
This sensor uses a Hall IC (element).
The cam position is determined by the intake primary cam sprocket
concave (in three places). The ECM provides feedback to the
intake valve timing control for appropriate target valve open-close
timing according to drive conditions based on detected cam posi-
tion.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0706Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
INT/V TIM (B1)
INT/V TIM (B2)IEngine: After warming up
IShift lever ªNº
IQuickly depressed accelerator
pedal
INo-loadIdle 0É CA
2,000 rpm Approximately 12 - 18É CA
ECM Terminals and Reference ValueNBEC0707Specification 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 the ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
79 Y/GIntake valve timing
control position sen-
sors (RH)[Engine is running]
IWarm-up condition
IIdle speedApproximately 0.5V
SEF351Z
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.Approximately 0.5V
SEF352Z
DTC P1140 (RIGHT, -B1), P1145 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
POSITION SENSOR (CIRCUIT)
Component Description
EC-482

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
89 ORIntake valve timing
control position sen-
sors (LH)[Engine is running]
IWarm-up condition
IIdle speedApproximately 0.5V
SEF351Z
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.Approximately 0.5V
SEF352Z
On Board Diagnosis LogicNBEC0708Malfunction is detected when an excessively high or low voltage
from the sensor is sent to ECM.
Possible CauseNBEC0709IHarness or connectors
(Intake valve timing control position sensor circuit is open or
shorted)
IIntake valve timing control position sensor.
ICrankshaft position sensor (REF)
ICrankshaft position sensor (POS)
ICamshaft position sensor (PHASE)
SEF353Z
DTC Confirmation ProcedureNBEC0710NOTE:
If ªDTC Confirmation Procedureº has been previously
conducted, always turn ignition switch ªOFFº and wait at least
10 seconds before conducting the next test.
WITH CONSULT-IINBEC0710S011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Maintain the following conditions for at least 10 seconds.
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PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1140 (RIGHT, -B1), P1145 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
POSITION SENSOR (CIRCUIT)
ECM Terminals and Reference Value (Cont'd)
EC-483

Engine speed More than Idle speed
Selector lever ªPº or ªNº position
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-487.
WITH GSTNBEC0710S02Follow the procedure ªWith CONSULT-IIº above.
DTC P1140 (RIGHT, -B1), P1145 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
POSITION SENSOR (CIRCUIT)
DTC Confirmation Procedure (Cont'd)
EC-484

Diagnostic ProcedureNBEC0712
1 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
SEF959Y
©GO TO 2.
2 CHECK INTAKE VALVE TIMING CONTROL POSITION SENSOR POWER SUPPLY CIRCUIT
1. Disconnect intake valve timing control position sensor harness connector.
SEF360Z
2. Turn ignition switch ªONº.
3. Check voltage between intake valve timing control position sensor harness connector terminal 3 and ground with CON-
SULT-II or tester.
SEF370X
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 4.
NG©GO TO 3.
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LC
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PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1140 (RIGHT, -B1), P1145 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
POSITION SENSOR (CIRCUIT)
Diagnostic Procedure
EC-487

3 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M32, F23
IHarness connectors E1, M1
IHarness for open or short between ECM and intake valve timing control position sensor
IHarness for open or short between ECM relay and intake valve timing control position sensor
©Repair open circuit or short to ground or short to power in harness or connectors.
4 CHECK INTAKE VALVE TIMING CONTROL POSITION SENSOR GROUND CIRCUIT FOR OPEN AND
SHORT
1. Turn ignition switch ªOFFº.
2. Check harness connector continuity between intake valve timing control position sensor harness connector terminal 1
and engine ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 5.
NG©Repair open circuit or short to power in harness or connectors.
5 CHECK INTAKE VALVE TIMING CONTROL POSITION SENSOR INPUT SIGNAL CIRCUIT
1. Disconnect ECM harness connector.
2. Check harness connectors continuity between ECM terminal 79 (Right) or 89 (Left) and terminal 2. Refer to Wiring Dia-
gram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 6.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK INTAKE VALVE TIMING CONTROL POSITION SENSOR INSTALLATION
Check that intake valve timing control position sensor is installed correctly as shown below.
SEF361Z
OK or NG
OK©GO TO 7.
NG©Install intake valve timing control position sensor correclty.
DTC P1140 (RIGHT, -B1), P1145 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
POSITION SENSOR (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-488

On Board Diagnosis LogicNBEC0282HThe closed loop control has the one trip detection logic.
Malfunction is detected when the closed loop control function for
right bank does not operate even when vehicle is driving in the
specified condition, the closed loop control function for left bank
does not operate even when vehicle is driving in the specified
condition.
Possible CauseNBEC0531IThe front heated oxygen sensor circuit is open or shorted.
IHeated oxygen sensor 1 (front)
IHeated oxygen sensor 1 heater (front)
DTC Confirmation ProcedureNBEC0283CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
INever raise engine speed above 3,600 rpm during the
ªDTC Confirmation Procedureº. If the engine speed limit is
exceeded, retry the procedure from step 2.
IBefore performing the following procedure, confirm that
battery voltage is more than 11V at idle.
SEF063Y
WITH CONSULT-IINBEC0283S011) Start engine and warm it up to normal operating temperature.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Hold engine speed at 2,000 rpm and check one of the follow-
ing.
IªHO2S1 (B1)/(B2)º voltage should go above 0.70V at least
once.
IªHO2S1 (B1)/(B2)º voltage should go below 0.21V at least
once.
If the check result is NG, perform ªDiagnosis Procedureº,
EC-492.
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TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
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IDX
DTC P1148 (RIGHT BANK, -B1), P1168 (LEFT BANK, -B2) CLOSED LOOP
CONTROL
On Board Diagnosis Logic
EC-491

If the check result is OK, perform the following step.
4) Let engine idle at least 5 minutes.
5) Maintain the following condition at least 50 consecutive sec-
onds.
B/FUEL SCHDL 3.6 msec or more
ENG SPEED 1,500 rpm or more
Selector lever Suitable position
VHCL SPEED SE More than 70 km/h (43 MPH)
During this test, P0130 and/or P0150 may be displayed on
CONSULT-II screen.
6) If DTC is detected, go to ªDiagnostic Procedureº, EC-492.
SEF308XB
Overall Function CheckNBEC0284Use this procedure to check the overall function of the closed loop
control. During this check, a DTC might not be confirmed.
WITH GSTNBEC0284S011) Start engine and warm it up to normal operating temperature.
2) Set voltmeter probes between ECM terminal 63 [Heated oxy-
gen sensor 1 (front) right bank signal] or 62 [Heated oxygen
sensor 1 (front) left bank signal] and engine ground.
3) Check the following with engine speed held at 2,000 rpm con-
stant under no-load.
IThe voltage should go above 0.70V at least once.
IThe voltage should go below 0.21V at least once.
4) If NG, go to ªDiagnostic Procedureº, EC-492.
Diagnostic ProcedureNBEC0285Perform trouble diagnosis for ªDTC P0133, P0153º, EC-218.
DTC P1148 (RIGHT BANK, -B1), P1168 (LEFT BANK, -B2) CLOSED LOOP
CONTROL
DTC Confirmation Procedure (Cont'd)
EC-492

SEF999Y
Component DescriptionNBEC0532The swirl control valve control vacuum check switch detects
vacuum signal to the swirl control valve, and sends ªONº or ªOFFº
signal to the ECM.
When vacuum is supplied to the valve, the swirl control valve con-
trol vacuum check switch sends ªOFFº signal to the ECM.
The swirl control valve control vacuum check switch is not used to
control the engine system, it is used for on board diagnosis.
SEF446Z
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0533Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
SWL CON VC SWIEngine speed: Idle
IEngine coolant temperature is between 15ÉC (59ÉF) to 50ÉC (122ÉF).OFF
IEngine speed: Idle
IEngine coolant temperature is above 55ÉC (131ÉF).ON
ECM Terminals and Reference ValueNBEC0674Specification 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.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
55 W/BSwirl control valve con-
trol vacuum check
switch[Engine is running]
IIdle speed
IEngine coolant temperature is between 15 to
50ÉC (59 to 122ÉF).Approximately 5V
[Engine is running]
IIdle speed
IEngine coolant temperature is above 55ÉC
(122ÉF).0 - 1.0V
GI
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DTC P1165 SWIRL CONTROL VALVE CONTROL VACUUM CHECK SWITCH
Component Description
EC-493