2001 INFINITI QX4 timing

8 CHECK FUEL PRESSURE
1. Install all removed parts.
2. Release fuel pressure to zero. Refer to EC-39.
3. Install fuel pressure gauge and check fuel pressure. Refer to EC-39.
At idle:
Approx. 235 kPa (2.4 kg/cm
2, 34 psi)
OK or NG
OK©GO TO 10.
NG©GO TO 9.
9 DETECT MALFUNCTIONING PART
Check the following.
IFuel pump and circuit (Refer to EC-625.)
IFuel pressure regulator (Refer to EC-40.)
IFuel lines (Refer to MA-16, ªChecking Fuel Linesº.)
IFuel filter for clogging
©Repair or replace.
10 CHECK IGNITION TIMING
Check the following items. Refer to ªBasic Inspectionº, EC-101.
MTBL0655
OK or NG
OK (With CONSULT-II)©GO TO 11.
OK (Without CONSULT-
II)©GO TO 12.
NG©Follow the ªBasic Inspectionº.
DTC P0300 - P0306 NO.6-1CYLINDER MISFIRE, MULTIPLE CYLINDER
MISFIRE
Diagnostic Procedure (Cont'd)
EC-324

SEF484Y
On Board Diagnosis LogicNBEC0214The ECM monitors the switching frequency ratio of heated oxygen
sensors 1 (front) and 2 (rear).
A warm-up three way catalyst with high oxygen storage capacity
will indicate a low switching frequency of rear heated oxygen sen-
sor. As oxygen storage capacity decreases, the rear heated oxy-
gen sensor switching frequency will increase.
When the frequency ratio of front and rear heated oxygen sensors
approaches a specified limit value, the warm-up three way catalyst
malfunction is diagnosed.
Malfunction is detected when warm-up three way catalyst does not
operate properly, warm-up three way catalyst does not have
enough oxygen storage capacity.
Possible CauseNBEC0504IWarm-up three way catalyst
IExhaust tube
IIntake air leaks
IInjectors
IInjector leaks
ISpark plug
IImproper ignition timing
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0420 (RIGHT BANK, -B1), P0430 (LEFT BANK, -B2) THREE WAY
CATALYST FUNCTION
On Board Diagnosis Logic
EC-347

4 CHECK IGNITION TIMING
Check the following items. Refer to ªBasic Inspectionº, EC-101.
MTBL0655
OK or NG
OK©GO TO 5.
NG©Follow the ªBasic Inspectionº.
5 CHECK INJECTORS
1. Refer to WIRING DIAGRAM for Injectors, EC-617.
2. Stop engine and then turn ignition switch ªONº.
3. Check voltage between ECM terminals 101, 102, 103, 104, 105, 107 and ground with CONSULT-II or tester.
SEF331X
OK or NG
OK©GO TO 6.
NG©Perform ªDiagnostic Procedureº, ªINJECTORº, EC-618.
DTC P0420 (RIGHT BANK, -B1), P0430 (LEFT BANK, -B2) THREE WAY
CATALYST FUNCTION
Diagnostic Procedure (Cont'd)
EC-350

4 CHECK IGNITION TIMING AND ENGINE IDLE SPEED
Check the following items. Refer to ªBasic Inspectionº, EC-101.
MTBL0656
Models with CONSULT-II©GO TO 6.
Models without CON-
SULT-II©GO TO 6.
5 CHECK THROTTLE POSITION SWITCH
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch ªOFFº.
3. Remove vacuum hose connected to throttle opener.
4. Connect suitable vacuum hose to vacuum pump and the throttle opener.
5. Apply vacuum [more than þ40.0 kPa (þ300 mmHg, þ11.81 inHg)] until the throttle drum becomes free from the rod of
the throttle opener.
SEF793W
6. Turn ignition switch ªONº.
7. Select ªDATA MONITORº mode with CONSULT-II.
8. Check indication of ªCLSD THL/P SWº under the following conditions.
Measurement must be made with throttle position switch installed in vehicle.
MTBL0355
OK or NG
OK (With CONSULT-II)©GO TO 8.
OK (Without CONSULT-
II)©GO TO 9.
NG©GO TO 7.
DTC P0510 CLOSED THROTTLE POSITION SWITCH
Diagnostic Procedure (Cont'd)
EC-436

DescriptionNBEC0691SYSTEM DESCRIPTIONNBEC0691S01
Sensor Input signal to ECM function ECM Actuator
Crankshaft positon sensor (POS) Engine speed (POS)
Intake valve
timing con-
trolIntake valve timing control sole-
noid valve Crankshaft position sensor (REF) Engine speed (REF)
Camshaft position sensor Engine speed
Engine coolant temperature sensor Engine coolant temperature
Vehicle speed sensor Vehicle speed
JEF349Z
This mechanism hydraulically controls cam phases continuously with the fixed operating angle of the intake
valve.
The ECM receives signals such as crankshaft position, camshaft position, engine speed, and engine coolant
temperature. Then, the ECM sends ON/OFF pulse duty signals to the camshaft timing control valve depend-
ing on driving status. This makes it possible to control the shut/open timing of the intake valve to increase
engine torque in low/mid speed range and output in high-speed range.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0692Specification 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
INT/V SOL (B1)
INT/V SOL (B2)IEngine: After warming up
IShift lever ªNº
IQuickly depressed accelerator
pedal
INo-loadIdle 0%
2,000 rpm Approximately 40%
DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
Description
EC-446

ECM Terminals and Reference Value=NBEC0693Specification data are reference values, and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring voltage. Doing so may result in damage 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)
13 OR/BIntake valve timing
control solenoid valves
(RH)[Engine is running]
IWarm-up condition
IIdle speedBattery voltage
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.7-8V
SEF350Z
15 P/LIntake valve timing
control solenoid valves
(LH)[Engine is running]
IWarm-up condition
IIdle speedBattery voltage
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.7-8V
SEF350Z
79 Y/GIntake valve timing
control position sen-
sors (RH)[Engine is running]
IWarm-up condition
IIdle speedApproximately 0.5VSEF351Z
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.Approximately 0.5V
SEF352Z
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
ECM Terminals and Reference Value
EC-447

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 LogicNBEC0694Malfunction is detected when:
(Malfunction A)
The alignment of the intake valve timing control has been misreg-
istered.
(Malfunction B)
There is a gap between angle of target and phase-control angle
degree.
FAIL-SAFE MODENBEC0694S01When malfunction A or B is detected, the ECM enters fail-safe
mode and the MIL lights up.
Detected items Engine operating condition in fail-safe mode
Intake valve timing control The signal is not energized to the solenoid valve and the valve control does not function.
Possible CauseNBEC0695MALFUNCTION A OR BNBEC0695S01IHarness or connectors
(Intake valve timing control position sensor circuit is open or
shorted.) Refer to EC-482.
ICrankshaft position sensor (REF)
ICrankshaft position sensor (POS)
ICamshaft position sensor (PHASE)
DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
ECM Terminals and Reference Value (Cont'd)
EC-448

DTC Confirmation ProcedureNBEC0696CAUTION:
Always drive at a safe speed.
NOTE:
IIf both DTC P1111(B1), P1136 (B2) or P1140 (B1), P1145
(B2) and P1110 (B1), P1135 (B2) are displayed, perform
trouble diagnosis for ªDTC P1111(B1), P1136 (B2) or
P1140 (B1), P1145 (B2)º first. (See EC-451, 482.)
IIf ªDTC Confirmation Procedureº has been previously
conducted, always turn ignition switch ªOFFº and wait at
least 10 seconds before conducting the next test.
SEF353Z
PROCEDURE FOR MALFUNCTION ANBEC0696S01With CONSULT-IINBEC0696S01011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Maintain the following conditions for at least 10 consecutive
seconds.
ENG SPEED More than 2,000 rpm
COOLANT TEMPS More than 70ÉC (158ÉF)
Selector lever 1st position
Driving locationDriving vehicle uphill
(Increased engine load will help main-
tain the driving conditions required for
this test.)
4) Maintain the following conditions for at least 20 consecutive
seconds.
ENG SPEED Idle
COOLANT TEMPS More than 70ÉC (158ÉF)
Selector lever ªPº or ªNº position
5) If 1st trip DTC is detected, go to ªP1140, P1145 INTAKE
VALVE TIMING CONTROL POSITION SENSORº. Refer to
EC-482.
With GSTNBEC0696S0102Follow the procedure ªWith CONSULT-IIº above.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
DTC Confirmation Procedure
EC-449