2001 INFINITI QX4 engine coolant

4) Make sure that A/C switch is ªOFFº and air conditioner is not
operating. If NG, check air conditioner circuit. Refer to HA-35
or HA-30, ªTROUBLE DIAGNOSESº. After repair, go to the
next step.
5) Check for blocked coolant passage.
a) Warm up engine to normal operating temperature, then grasp
radiator upper hose and lower hose and make sure that cool-
ant flows.
If NG, go to ªDiagnostic Procedureº, EC-316. After repair, go
to the next step.
Be extremely careful not to touch any moving or adjacent
parts.
6) Check for blocked radiator air passage.
a) When market fog lamps have been installed, check for dam-
aged fans and clogging in the condenser and radiator.
b) Check the front end for clogging caused by insects or debris.
c) Check for improper fitting of front-end cover, damaged radia-
tor grille or bumper, damaged vehicle front.
If NG, take appropriate action and then go to the next step.
7) Check function of ECT sensor.
Refer to step 6 of ªDiagnostic Procedureº, EC-316.
If NG, replace ECT sensor and go to the next step.
8) Check ignition timing. Refer to basic inspection, EC-101.
Make sure that ignition timing is 15ɱ5É at idle.
If NG, adjust ignition timing and then recheck.
Diagnostic ProcedureNBEC0614
1 CHECK COOLING SYSTEM FOR LEAK
Apply pressure to the cooling system with a tester, and check if the pressure drops.
Testing pressure: 157 kPa (1.6 kg/cm2, 23 psi)
CAUTION:
Higher than the specified pressure may cause radiator damage.
SLC754A
Pressure should not drop.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
DTC P0217 COOLANT OVERTEMPERATURE ENRICHMENT PROTECTION
Overall Function Check (Cont'd)
EC-316

5 CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Remove engine coolant temperature sensor.
2. Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in the figure.
SEF304X
OK or NG
OK©GO TO 6.
NG©Replace engine coolant temperature sensor.
6 CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to ªMAIN 12 CAUSES OF OVERHEATINGº, EC-319.
©INSPECTION END
DTC P0217 COOLANT OVERTEMPERATURE ENRICHMENT PROTECTION
Diagnostic Procedure (Cont'd)
EC-318

Main 12 Causes of OverheatingNBEC0615
Engine Step Inspection item Equipment Standard Reference page
OFF 1IBlocked radiator
IBlocked condenser
IBlocked radiator grille
IBlocked bumperIVisual No blocking Ð
2ICoolant mixtureICoolant tester 50 - 50% coolant mixture See MA-11, ªRECOM-
MENDED FLUIDS AND
LUBRICANTSº.
3ICoolant levelIVisual Coolant up to MAX level
in reservoir tank and
radiator filler neckSee MA-14, ªChanging
Engine Coolantº.
4IRadiator capIPressure tester 59 - 98 kPa
(0.6 - 1.0 kg/cm
2,9-14
psi) (Limit)See LC-11, ªSystem
Checkº.
ON*
25ICoolant leaksIVisual No leaks See LC-11, ªSystem
Checkº.
ON*
26IThermostatITouch the upper and
lower radiator hosesBoth hoses should be
hotSee LC-16, ªThermostatº
and LC-19, ªRadiatorº.
ON*
17*5ICooling fanICONSULT-II Operating See trouble diagnosis for
DTC P0217 (EC-314).
OFF 8ICombustion gas leakIColor checker chemi-
cal tester 4 Gas ana-
lyzerNegative Ð
ON*
39ICoolant temperature
gaugeIVisual Gauge less than 3/4
when drivingÐ
ICoolant overflow to
reservoir tankIVisual No overflow during driv-
ing and idlingSee MA-14, ªChanging
Engine Coolantº.
OFF*
410ICoolant return from
reservoir tank to radia-
torIVisual Should be initial level in
reservoir tankSee MA-13, ªENGINE
MAINTENANCEº.
OFF 11ICylinder headIStraight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)See EM-42, ªInspectionº.
12ICylinder block and pis-
tonsIVisual No scuffing on cylinder
walls or pistonSee EM-63, ªInspectionº.
*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
*5: Cooling fan is not applied to this vehicle.
For more information, refer to LC-24, ªOVERHEATING CAUSE ANALYSISº.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0217 COOLANT OVERTEMPERATURE ENRICHMENT PROTECTION
Main 12 Causes of Overheating
EC-319

DescriptionNBEC0221SYSTEM DESCRIPTIONNBEC0221S01
Sensor Input Signal to ECMECM
functionActuator
Crankshaft position sensor (POS) Engine speed (POS signal)
EVAP can-
ister purge
flow controlEVAP canister purge volume
control solenoid valve Crankshaft position sensor (REF) Engine speed (REF signal)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Throttle position switch Closed throttle position
Heated oxygen sensor 1 (front)Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel tank temperature sensor Fuel temperature in fuel tank
Vehicle speed sensor Vehicle speed
This system controls flow rate of fuel vapor from the EVAP canis-
ter. The opening of the vapor by-pass passage in the EVAP canis-
ter purge volume control solenoid valve changes to control the flow
rate. The EVAP canister purge volume control solenoid valve
repeats ON/OFF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engine control.
The optimum value stored in the ECM is determined by consider-
ing various engine conditions. When the engine is operating, the
flow rate of fuel vapor from the EVAP canister is regulated as the
air flow changes.
SEF337U
COMPONENT DESCRIPTIONNBEC0221S02The EVAP canister purge volume control solenoid valve uses a
ON/OFF duty to control the flow rate of fuel vapor from the EVAP
canister. The EVAP canister purge volume control solenoid valve
is moved by ON/OFF pulses from the ECM. The longer the ON
pulse, the greater the amount of fuel vapor that will flow through the
valve.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0222Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
PURG VOL C/VIEngine: After warming up
IAir conditioner switch ªOFFº
IShift lever: ªNº
INo-loadIdle (Vehicle stopped) 0%
2,000 rpm Ð
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0443 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
(CIRCUIT)
Description
EC-367

DescriptionNBEC0249SYSTEM DESCRIPTIONNBEC0249S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed (POS signal)
Idle air
controlIACV-AAC valve Crankshaft position sensor (REF) Engine speed (REF signal)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Park/neutral position (PNP) switch Park/neutral position
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Battery Battery voltage
Vehicle speed sensor Vehicle speed
Ambient air temperature switch Ambient air temperature
Intake air temperature sensor Intake air temperature
Absolute pressure sensor Ambient barometic pressure
This system automatically controls engine idle speed to a specified
level. Idle speed is controlled through fine adjustment of the
amount of air which by-passes the throttle valve via IACV-AAC
valve. The IACV-AAC valve changes the opening of the air by-pass
passage to control the amount of auxiliary air. This valve is actu-
ated by a step motor built into the valve, which moves the valve in
the axial direction in steps corresponding to the ECM output sig-
nals. One step of IACV-AAC valve movement causes the respec-
tive opening of the air by-pass passage. (i.e. when the step
advances, the opening is enlarged.) The opening of the valve is
varied to allow for optimum control of the engine idling speed. The
crankshaft position sensor (POS) detects the actual engine speed
and sends a signal to the ECM. The ECM then controls the step
position of the IACV-AAC valve so that engine speed coincides with
the target value memorized in ECM. The target engine speed is the
lowest speed at which the engine can operate steadily. The opti-
mum value stored in the ECM is determined by takig into consid-
eration various engine conditions, such as during warm up,
deceleration, and engine load (air conditioner, power steering and
cooling fan operation).
SEF765P
COMPONENT DESCRIPTIONNBEC0249S02IACV-AAC ValveNBEC0249S0201The IACV-AAC valve is operated by a step motor for centralized
control of auxiliary air supply. This motor has four winding phases
and is actuated by the output signals of ECM which turns ON and
OFF two windings each in seqeunce. Each time the IACV-AAC
valve opens or closes to change tha auxiliary air quantity, the ECM
sends a pulse signal to the step motor. When no change in the
auxiliary air quantity is needed, the ECM does not issue the pulse
signal. A certain voltage signal is issued so that the valve remains
at that particular opening.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
Description
EC-422

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

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

SEF353Z
PROCEDURE FOR MALFUNCTION B=NBEC0696S02With CONSULT-IINBEC0696S02011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Maintain the following conditions for at least 20 consecutive
seconds.
ENG SPEED2,000 - 3,000 rpm (A constant rotation
is maintained.)
COOLANT TEMPS 70 - 90ÉC (158 - 194ÉF)
Selector lever 1st or position
Driving location uphillDriving vehicle uphill
(Increased engine load will help main-
tain the driving conditions required for
this test.)
4) If 1st trip DTC is detected, go to ªP1140, P1145 INTAKE
VALVE TIMING CONTROL POSITION SENSORº. Refer to
EC-482.
With GSTNBEC0696S0202Follow the procedure ªWith CONSULT-IIº above.
DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
DTC Confirmation Procedure (Cont'd)
EC-450