2001 INFINITI QX4 radiator

4 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F112, F28
IHarness for open between ECM and engine coolant temperature sensor
IHarness for open between TCM (Transmission Control Module) and engine coolant temperature sensor
©Repair open circuit or short to power in harness or connectors.
5 CHECK ENGINE COOLANT TEMPERATURE SENSOR
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 THERMOSTAT OPERATION
When the engine is cold [lower than 70ÉC (158ÉF)] condition, grasp lower radiator hose and confirm the engine coolant
does not flow.
OK or NG
OK©GO TO 7.
NG©Repair or replace thermostat. Refer to LC-16, ªThermostatº.
7 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
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DTC P0125 ENGINE COOLANT TEMPERATURE SENSOR (ECTS)
Diagnostic Procedure (Cont'd)
EC-191

On Board Diagnosis LogicNBEC0610This diagnosis checks whether the engine coolant temperature is
extraordinary high, even when the load is not heavy.
When malfunction is detected, the malfunction indicator lamp (MIL)
will light up even in the first trip.
Malfunction is detected when engine coolant temperature is exces-
sively high under normal engine speed.
Possible CauseNBEC0611IThermostat
IImproper ignition timing
IEngine coolant temperature sensor
IBlocked radiator
IBlocked front end (Improper fitting of nose mask)
ICrushed vehicle frontal area (Vehicle frontal is collided but not
repaired)
IBlocked air passage by improper installation of front fog lamp
or fog lamps.
IImproper mixture ratio of coolant
IDamaged bumper
For more information, refer to ªMAIN 12 CAUSES OF
OVERHEATINGº, EC-319.
Overall Function CheckNBEC0612Use this procedure to check the overall function of the coolant
overtemperature enrichment protection check, a DTC might not be
confirmed.
WARNING:
Never remove the radiator cap when the engine is hot. Serious
burns could be caused by high-pressure fluid escaping from
the radiator.
Wrap a thick cloth around the cap. Carefully remove the cap
by turning it a quarter turn to allow built-up pressure to
escape. Then turn the cap all the way off.
SEF621W
WITH CONSULT-IINBEC0612S011) Check the coolant level and mixture ratio (using coolant tester)
in the reservoir tank and radiator.
Allow engine to cool before checking coolant level and
mixture ratio.
IIf the coolant level in the reservoir and/or radiator is below the
proper range, go to ªDiagnostic Procedureº, EC-316.
IIf the coolant mixture ratio is out of the range of 45 to 55%,
replace the coolant in the following procedure MA-14, ªChang-
ing Engine Coolantº.
a) Fill radiator with coolant up to specified level with a filling speed
DTC P0217 COOLANT OVERTEMPERATURE ENRICHMENT PROTECTION
On Board Diagnosis Logic
EC-314

of 2 liters per minute like pouring coolant from a kettle. Be sure
to use coolant with the proper mixture ratio. Refer to MA-12,
ªAnti-freeze Coolant Mixture Ratioº.
b) After refilling coolant, run engine to ensure that no water-flow
noise is emitted.
c) After checking or replacing coolant, go to step 3 below.
2) Ask the customer if engine coolant has been added. If it has
been added, go to ªDiagnostic Procedureº, EC-316. After
repair, go to the next step.
3) Start engine and let it idle.
4) Make sure that A/C switch is ªOFFº and air conditioner is not
operating. If NG, check air conditioner circuit. Refer to HA-30
or HA-35, 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 7 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.
WITH GSTNBEC0612S021) Check the coolant level and mixture ratio (using coolant tester)
in the reservoir tank and radiator.
Allow engine to cool before checking coolant level and
mixture ratio.
IIf the coolant level in the reservoir and/or radiator is below the
proper range, and go to ªDiagnostic Procedureº, EC-316.
IIf the coolant mixture ratio is out of the range of 45 to 55%,
replace the coolant in the following procedure MA-14, ªChang-
ing Engine Coolantº.
a) Fill radiator with coolant up to specified level with a filling speed
of 2 liters per minute like pouring coolant from a kettle. Be sure
to use coolant with the proper mixture ratio. Refer to MA-12,
ªAnti-freeze Coolant Mixture Ratioº.
b) After refilling coolant, run engine to ensure that no water-flow
noise is emitted.
c) After checking or replacing coolant, go to step 3 below.
2) Ask the customer if engine coolant has been added. If it has
been added, go to ªDiagnostic Procedureº, EC-316. After
repair, go to the next step.
3) Start engine and let it idle.
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DTC P0217 COOLANT OVERTEMPERATURE ENRICHMENT PROTECTION
Overall Function Check (Cont'd)
EC-315

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

2 DETECT MALFUNCTIONING PART
Check the following for leak.
IHose
IRadiator
IWater pump (Refer to LC-12, ªWater Pumpº.)
©Repair or replace.
3 CHECK RADIATOR CAP
Apply pressure to cap with a tester and check radiator cap relief pressure.
SLC755A
Radiator cap relief pressure:
59 - 98 kPa (0.6 - 1.0 kg/cm2,9-14psi)
OK or NG
OK©GO TO 4.
NG©Replace radiator cap.
4 CHECK THERMOSTAT
1. Remove thermostat.
2. Check valve seating condition at normal room temperatures.
It should seat tightly.
3. Check valve opening temperature and valve lift.
SLC343
Valve opening temperature:
76.5ÉC (170ÉF) [standard]
Valve lift:
More than 8.6 mm/90ÉC (0.339 in/194ÉF)
4. Check if valve is closed at 5ÉC (9ÉF) below valve opening temperature. For details, refer to LC-16, ªThermostatº.
OK or NG
OK©GO TO 5.
NG©Replace thermostat
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DTC P0217 COOLANT OVERTEMPERATURE ENRICHMENT PROTECTION
Diagnostic Procedure (Cont'd)
EC-317

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.
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DTC P0217 COOLANT OVERTEMPERATURE ENRICHMENT PROTECTION
Main 12 Causes of Overheating
EC-319

ComponentsNBEM0008
SEM583G
RemovalNBEM0009WARNING:
IPlace vehicle on a flat and solid surface.
IYou should not remove oil pan until exhaust system and
cooling system have completely cooled off.
Otherwise, you may burn yourself and/or fire may break
out in the fuel line.
IWhen removing front engine mounting nuts, lift up slightly
engine for safety work.
CAUTION:
When removing the aluminum oil pan from engine, first
remove the crankshaft position sensors (POS and REF) from
the assembly.
Be careful not to damage sensor edges and signal plate teeth.
1. Remove front RH and LH wheels.
2. Remove battery.
3. Remove oil level gauge.
4. Remove engine undercover.
5. Remove suspension member stay.
6. Drain engine coolant from radiator drain plug.
7. Disconnect A/T oil cooler hoses.
8. Drain engine oil.
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OIL PAN
Components
EM-15

CAUTION:
IAfter removing timing chain, do not turn crankshaft and
camshaft separately, or valves will strike piston heads.
IWhen installing camshafts, chain tensioners, oil seals, or
other sliding parts, lubricate contacting surfaces with new
engine oil.
IApply new engine oil to bolt threads and seat surfaces
when installing camshaft sprockets and crankshaft pulley.
IBefore disconnecting fuel hose, release fuel pressure.
Refer to EC-39, ªFuel Pressure Releaseº.
IBe careful not to damage sensor edges.
IDo not spill engine coolant on drive belts.
RemovalNBEM00121. Release fuel pressure.
Refer to EC-39, ªFuel Pressure Releaseº.
2. Remove battery.
3. Remove radiator.
Refer to LC-19, ªREMOVAL AND INSTALLATIONº.
4. Drain engine oil.
5. Remove drive belts and idler pulley with brackets.
6. Remove cooling fan with bracket.
7. Remove engine cover.
8. Remove air duct with air cleaner case, collector, blow-by hose,
vacuum hoses, fuel hoses, water hoses, wires, harnesses,
connectors and so on.
9. Remove the air compressor, and tie it down using rope or the
like to keep it from interfering.
10. Remove the power steering oil pump and reservoir tank. Tie
them down using rope or the like to keep them from interfer-
ing.
11. Remove alternator.
12. Remove the following.
IVacuum gallery
IWater bypass pipe
IBrackets
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TIMING CHAIN
Components (Cont'd)
EM-23