2005 INFINITI FX35 thermostat

DTC P0128 THERMOSTAT FUNCTION EC-227
[VQ35DE]
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Revision: 2005 July 2005 FX
Component InspectionABS006NP
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.

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) Resistance k Ω
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P

DTC P1217 ENGINE OVER TEMPERATURE EC-469
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Revision: 2005 July 2005 FX
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 engine Air conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates.) ON
COOLING FAN

Engine: After warming up, idle
the engine

Air conditioner switch: OFF Engine coolant temperature is 94
°C
(201 °F) or less OFF
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 more HI
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1217
1217 Engine 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-478,
"Main 12 Causes of Overheating" .

EC-474
[VQ35DE]
DTC P1217 ENGINE OVER TEMPERATURE
Revision: 2005 July 2005 FX
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-212, "
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-478, "
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-478
[VQ35DE]
DTC P1217 ENGINE OVER TEMPERATURE
Revision: 2005 July 2005 FX
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 mixture MA-13
3
Coolant level
Visual Coolant up to MAX level
in reservoir tank and radi-
ator filler neck CO-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 leaks
CO-11
ON*26
Thermostat
Touch the upper and
lower radiator hoses Both hoses should be hot
CO-26
ON*17
Cooling fan
CONSULT-II Operating See trouble diagnosis for
DTC P1217 ( EC-467
).
OFF 8

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

Coolant overflow to
reservoir tank
Visual No overflow during driving and idling CO-11
OFF*410
Coolant return from
reservoir tank to radia-
tor
Visual Should be initial level in reservoir tank CO-11
OFF 11
Cylinder head
Straight gauge feeler
gauge 0.1 mm (0.004 in) Maxi-
mum distortion (warping) EM-102
12
Cylinder block and pis-
tons
Visual No scuffing on cylinder walls or piston EM-122
Cooling fan speed
Cooling 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

TROUBLE DIAGNOSIS EC-797
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Revision: 2005 July 2005 FX
DTC Inspection Priority ChartABS007HZ
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC U1000 and/or U1001 is displayed with other DTC, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-862
.
Priority Detected items (DTC)
1

U1000 U1001 CAN communication line

P0101 P0102 P0103 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

P0700 TCM

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-803
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Revision: 2005 July 2005 FX
1 - 6: The numbers refer to the order of inspection. Cooling
Radiator/Hose/Radiator filler cap
55555 55 45 CO-41
,
CO-45
Thermostat 5 CO-53
Water pumpCO-51
Water galleryCO-35
Cooling fan
5 CO-49
Coolant level (Low)/Contami-
nated coolant CO-37
IVIS (INFINITI Vehicle Immobilizer System —
NATS) 11
EC-744 or
BL-213
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-927
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Revision: 2005 July 2005 FX
DTC P0125 ECT SENSORPFP:22630
Component DescriptionABS007KF
NOTE:
If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or
P0118. Refer to EC-914
.
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 LogicABS007KG
This self-diagnosis has the one trip detection logic.
SEF594K
Engine coolant
temperature °C ( °F) Voltage* V Resistance k
Ω
–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
0125 Insufficient 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-929
[VK45DE]
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Revision: 2005 July 2005 FX
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-53, "
THERMOSTAT AND WATER CONTROL VALVE" .
4. CHECK INTERMITTENT INCIDENT
Refer to EC-854, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
Refer to EC-916, "
Wiring Diagram" .
>> INSPECTION END
Component InspectionABS007KJ
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.

2. If NG, replace engine coolant temperature sensor.
Removal and InstallationABS007KK
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-53, "THERMOSTAT AND WATER CONTROL VALVE" .
PBIB2005E
Temperature °C ( °F) Resistance k Ω
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P