2004 INFINITI FX35 thermostat

EC-204
[VQ35DE]
DTC P0128 THERMOSTAT FUNCTION
Revision: 2004 November 2004 FX35/FX45
Component InspectionABS00D1K
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.

*: This data is reference value and is measured between ECM terminal 73
(Engine coolant temperature sensor) and ground.
2. If NG, replace engine coolant temperature sensor.
Removal and InstallationABS006NQ
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-26, "WATER INLET AND THERMOSTAT ASSEMBLY" .
PBIB2005E
Engine coolant
temperature°C (°F)Voltage* V Resistance kΩ
20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P

DTC P1217 ENGINE OVER TEMPERATURE
EC-475
[VQ35DE]
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Revision: 2004 November 2004 FX35/FX45
CONSULT-II Reference Value in Data Monitor ModeABS006V9
Specification data are reference values.
On Board Diagnosis LogicABS006VA
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
This self-diagnosis has the one trip detection logic.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant. Refer to CO-11, "
Changing Engine
Coolant" . Also, replace the engine oil. Refer to LU-9, "Changing Engine Oil" .
1. Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure to
use coolant with the proper mixture ratio. Refer to MA-13, "
Anti-Freeze Coolant Mixture Ratio" .
2. After refilling coolant, run engine to ensure that no water-flow noise is emitted.
Overall Function CheckABS006VB
Use this procedure to check the overall function of the cooling fan. During this check, a DTC might not be con-
firmed.
WARNING:
Never remove the radiator cap when the engine is hot. Serious burns could be caused by high pres-
sure fluid escaping from the radiator.
Wrap a thick cloth around 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.
MONITOR ITEM CONDITION SPECIFICATION
AIR COND SIG

Engine: After warming up, idle
the engineAir conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates.)ON
COOLING FAN

Engine: After warming up, idle
the engine

Air conditioner switch: OFFEngine coolant temperature is 94°C
(201°F) or lessOFF
Engine coolant temperature is
between 95°C (203°F) and 99°C
(210°F)LOW
Engine coolant temperature is
between 100°C (212°F) and 104°C
(219°F)MID
Engine coolant temperature is 105°C
(221°F) or moreHI
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1217
1217Engine over tempera-
ture (Overheat)

Cooling fan does not operate properly (Over-
heat).

Cooling fan system does not operate prop-
erly (Overheat).

Engine coolant level was not added to the
system using the proper filling method.

Engine coolant is not within the specified
range.

Harness or connectors
(The cooling fan circuit is open or
shorted.)

IPDM E/R

Cooling fan

Radiator hose

Radiator

Radiator cap

Water pump

Thermostat
For more information, refer to EC-484,
"Main 12 Causes of Overheating" .

EC-480
[VQ35DE]
DTC P1217 ENGINE OVER TEMPERATURE
Revision: 2004 November 2004 FX35/FX45
5. CHECK RADIATOR CAP
Apply pressure to cap with a tester.
OK or NG
OK >> GO TO 6.
NG >> Replace radiator cap.
6. CHECK THERMOSTAT
1. Check valve seating condition at normal room temperatures.
It should seat tightly.
2. Check valve opening temperature and valve lift.
3. Check if valve is closed at 5°C (9°F) below valve opening tem-
perature.
For details, refer to CO-26, "
WATER INLET AND THERMO-
STAT ASSEMBLY" .
OK or NG
OK >> GO TO 7.
NG >> Replace thermostat
7. CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-189, "
Component Inspection" .
OK or NG
OK >> GO TO 8.
NG >> Replace engine coolant temperature sensor.
8. CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to EC-484, "
Main 12 Causes of Overheating" .
>>INSPECTION END Radiator cap relief pressure:
59 - 98 kPa (0.6 - 1.0 kg/cm
2
, 9 - 14 psi)
SLC755A
Valve opening temperature: 76.5°C (170°F) [standard]
Valve lift: More than 8.6 mm/90°C
(0.339 in/194°F)
SLC343

EC-484
[VQ35DE]
DTC P1217 ENGINE OVER TEMPERATURE
Revision: 2004 November 2004 FX35/FX45
Main 12 Causes of OverheatingABS006VE
*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.
For more information, refer to CO-7, "
OVERHEATING CAUSE ANALYSIS" .
Component InspectionABS006VF
COOLING FAN MOTORS-1 AND -2
1. Disconnect cooling fan motor harness connectors.
2. Supply cooling fan motor terminals with battery voltage and
check operation.
Cooling fan motor should operate.
If NG, replace cooling fan motor.
Engine Step Inspection item Equipment Standard Reference page
OFF 1

Blocked radiator

Blocked condenser

Blocked radiator grille

Blocked bumper

Visual No blocking —
2

Coolant mixture
Coolant tester 50 - 50% coolant mixtureMA-13
3
Coolant level
Visual Coolant up to MAX level
in reservoir tank and radi-
ator filler neckCO-11
4
Radiator cap
Pressure tester 59 - 98 kPa
(0.6 - 1.0 kg/cm2 , 9 - 14
psi) (Limit)CO-15
ON*25
Coolant leaks
Visual No leaksCO-11
ON*26
Thermostat
Touch the upper and
lower radiator hosesBoth hoses should be hotCO-26
ON*17
Cooling fan
CONSULT-II Operating See trouble diagnosis for
DTC P1217 (EC-472
).
OFF 8

Combustion gas leak
Color checker chemical
tester 4 Gas analyzerNegative —
ON*
39
Coolant temperature
gauge
Visual Gauge less than 3/4
when driving—

Coolant overflow to
reservoir tank
Visual No overflow during driving
and idlingCO-11
OFF*410
Coolant return from
reservoir tank to radia-
tor
Visual Should be initial level in
reservoir tankCO-11
OFF 11
Cylinder head
Straight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)EM-100
12
Cylinder block and pis-
tons
Visual No scuffing on cylinder
walls or pistonEM-120
Cooling fan speedCooling fan motor terminals
(+) (−)
Middle (MID)1 3 and 4
2 3 and 4
1 and 2 3
1 and 2 4
High (HI) 1 and 2 3 and 4
SEF734W

EC-730
[VK45DE]
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
Priority Detected items (DTC)
1

U1000 U1001 CAN communication line

P0101 P0102 P0103 P1102 Mass air flow sensor

P0112 P0113 P0127 Intake air temperature sensor

P0117 P0118 P0125 Engine coolant temperature sensor

P0122 P0123 P0222 P0223 P1225 P1226 P2135 Throttle position sensor

P0128 Thermostat function

P0181 P0182 P0183 Fuel tank temperature sensor

P0327 P0328 P0332 P0333 Knock sensor

P0335 Crankshaft position sensor (POS)

P0340 Camshaft position sensor (PHASE)

P0460 P0461 P0462 P0463 Fuel level sensor

P0500 Vehicle speed sensor

P0605 ECM

P0705 Park/Neutral position (PNP) switch

P1229 Sensor power supply

P1610 - P1615 NATS

P1706 Park/Neutral position (PNP) switch

P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor

TROUBLE DIAGNOSIS
EC-741
[VK45DE]
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EC
Revision: 2004 November 2004 FX35/FX45
1 - 6: The numbers refer to the order of inspection.Exhaust Exhaust manifold/Tube/Muffler/
Gasket
55555 55 5EM-178
,
EX-3
Three way catalyst
Lubrica-
tionOil pan/Oil strainer/Oil pump/Oil
filter/Oil gallery/Oil cooler
55555 55 5EM-181
,
LU-31
, LU-
28 , LU-29
Oil level (Low)/Filthy oilLU-25
Cooling
Radiator/Hose/Radiator filler cap
55555 55 45CO-39,
CO-43
Thermostat 5CO-51
Water pumpCO-49
Water galleryCO-34
Cooling fan
5CO-47
Coolant level (Low)/Contami-
nated coolantCO-36
IVIS (INFINITI Vehicle Immobilizer System —
NATS)11EC-717 or
BL-206
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA

DTC P0125 ECT SENSOR
EC-855
[VK45DE]
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Revision: 2004 November 2004 FX35/FX45
DTC P0125 ECT SENSORPFP:22630
Component DescriptionABS00C26
NOTE:
If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or
P0118. Refer to EC-842
.
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant
temperature input. The sensor uses a thermistor which is sensitive to
the change in temperature. The electrical resistance of the ther-
mistor decreases as temperature increases.

*: These data are reference values and are measured between ECM terminal 73
(Engine coolant temperature sensor) 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.
On Board Diagnosis LogicABS00C27
This self-diagnosis has the one trip detection logic.
SEF594K
Engine coolant
temperature°C (°F)Voltage* V Resistance kΩ
-10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0125
0125Insufficient engine cool-
ant temperature for
closed loop fuel control

Voltage sent to ECM from the sensor is not
practical, even when some time has passed
after starting the engine.

Engine coolant temperature is insufficient for
closed loop fuel control.

Harness or connectors
(High resistance in the circuit)

Engine coolant temperature sensor

Thermostat

DTC P0125 ECT SENSOR
EC-857
[VK45DE]
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Revision: 2004 November 2004 FX35/FX45
3. CHECK THERMOSTAT OPERATION
When the engine is cold [lower than 70°C (158°F)] condition, grasp lower radiator hose and confirm the engine
coolant does not flow.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace thermostat. Refer to CO-51, "
THERMOSTAT AND WATER CONTROL VALVE" .
4. CHECK INTERMITTENT INCIDENT
Refer to EC-784, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionABS00C2A
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.

*: These data are reference values and are measured between ECM terminal
73 (Engine coolant temperature sensor) and ground.
2. If NG, replace engine coolant temperature sensor.
Removal and InstallationABS00C2B
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-51, "THERMOSTAT AND WATER CONTROL VALVE" .
PBIB2005E
Engine coolant
temperature°C (°F)Voltage* V Resistance kΩ
20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P