2008 INFINITI FX35 engine overheat

EC-204
< SERVICE INFORMATION >[VQ35DE]
DTC P0125 ECT SENSOR
DTC P0125 ECT SENSOR
Component DescriptionINFOID:0000000001326028
NOTE:
If DTC P0125 is displayed with P0117 or P0118, fi
rst perform the trouble diagnosis for DTC P0117 or
P0118. Refer to EC-193
.
The engine coolant temperature (ECT) 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 sens or uses a thermistor which is
sensitive to the change in temperat ure. The electrical resistance of
the thermistor decreases as temperature increases.

*: This data is reference values and is measured between ECM terminal 73 (Engine
coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000001326029
DTC Confirmation ProcedureINFOID:0000000001326030
CAUTION:
Be careful not to overheat engine.
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Check that “COOLAN TEMP/S” is above 10 °C (50 °F).
If it is above 10 °C (50 °F), the test result will be OK.
If it is below 10 °C (50 °F), go to following step.
4. Start engine and run it for 65 minutes at idle speed.
SEF594K
Engine coolant
temperature °C ( °F) Voltage* V Resistance k
Ω
-10 (14) 4.4 7.0 - 11.4s 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
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DTC P1217 ENGINE OVER TEMPERATUREEC-439
< SERVICE INFORMATION > [VQ35DE]
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CAUTION:
When a malfunction is in
dicated, be sure to replace the coolant. Refer to CO-10, "
Changing Engine
Coolant". Also, replace the engine oil. Refer to LU-7, "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-10, "
Anti-Freeze Coolant Mixture Ratio".
2. After refilling coolant, run engine to ensure that no water-flow noise is emitted.
Overall Function CheckINFOID:0000000001326294
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 ca p by turning it a quarter turn to allow built-up
pressure to escape. Then turn the cap all the way off.
WITH CONSULT-III
1. Check the coolant level in the reservoir tank and radiator.
Allow engine to cool befo re checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to EC-441,
"Diagnosis Procedure".
2. Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to EC-441,
"Diagnosis Procedure".
3. Turn ignition switch ON.
4. Perform “COOLING FAN” in “ACTIVE TEST” mode with CON-
SULT-III.
5. If the results are NG, go to EC-441, "
Diagnosis Procedure".
WITH GST
1. Check the coolant level in the reservoir tank and radiator.
Allow engine to cool befo re checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to EC-441,
"Diagnosis Procedure".
2. Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to EC-441,
"Diagnosis Procedure".
3. Perform IPDM E/R auto active test and check cooling fan motors operation, refer to PG-20, "
Auto Active Test"
4. If NG, go to EC-441, "Diagnosis Procedure".
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 proper- ly (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
(Cooling fan circuit is open or shorted.)
 IPDM E/R
 Cooling fan
 Radiator hose
Radiator
Radiator cap
 Water pump
Thermostat
For more informat ion, refer to EC-445,
"Main 12 Causes of Overheating".
SEF621W
SEF621W
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EC-442
< SERVICE INFORMATION >[VQ35DE]
DTC P1217 ENGINE
OVER TEMPERATURE
No >> GO TO 3.
2.CHECK COOLING FAN OPERATION
With CONSULT-III
1. Start engine and let it idle.
2. Select “COOLING FAN” in “ACTIVE TEST” mode with CONSULT-III.
3. Make sure that cooling fans-1 and -2 operate at each speed (LOW/MID/HI).
OK or NG
OK >> GO TO 4.
NG >> Check cooling fan control circuit. (Go to “PROCEDURE B”.)
3.CHECK COOLING FAN OPERATION
Without CONSULT-III
1. Perform IPDM E/R auto active test and check cooling fan motors operation, refer to PG-20, "
Auto Active
Te s t".
2. Make sure that cooling fans-1 and -2 operate at each speed (Low/Middle/High).
OK or NG
OK >> GO TO 4.
NG >> Check cooling fan control circuit. (Go to “PROCEDURE B”.)
4.CHECK COOLING SYSTEM FOR LEAK
Refer to CO-10, "
Inspection".
OK or NG
OK >> GO TO 5.
NG >> Check the following for leak. Hose
 Radiator
 Water pump
5.CHECK RADIATOR CAP
Refer to CO-14, "
Checking Radiator Cap".
OK or NG
OK >> GO TO 6.
NG >> Replace radiator cap.
6.CHECK THERMOSTAT
Refer to CO-27
.
OK or NG
OK >> GO TO 7.
NG >> Replace thermostat
7.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-197, "
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-445, "
Main 12 Causes of Overheating".
>> INSPECTION END
PROCEDURE B
1.CHECK COOLILNG FAN POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R harness connectors E6.
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DTC P1217 ENGINE OVER TEMPERATUREEC-445
< SERVICE INFORMATION > [VQ35DE]
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Check the following.
 Harness connectors E29, E121
 Harness for open or short between cooling fan motor-2 and IPDM E/R
>> Repair open circuit or short to ground or short to power in harness or connectors.
12.CHECK COOLING FAN MOTORS
Refer to EC-446, "
Component Inspection".
OK or NG
OK >> GO TO 13.
NG >> Replace malfunctioning cooling fan motors.
13.CHECK INTERMITTENT INCIDENT
Perform EC-139
.
OK or NG
OK >> Replace IPDM E/R. Refer to PG-17.
NG >> Repair or replace harness or connector.
Main 12 Causes of OverheatingINFOID:0000000001326297
*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
.
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-10, "
Anti-Freeze
Coolant Mixture Ratio"
3  Coolant level  Visual Coolant up to MAX level in
reservoir tank and radiator
filler neckCO-10, "Changing Engine
Coolant"
4  Radiator cap  Pressure tester 59 - 98 kPa
(0.6 - 1.0 kg/cm2, 9 - 14
psi) (Limit) CO-14, "
Checking Radia-
tor Cap"
ON*25  Coolant leaks  Visual No leaks
CO-10, "Inspection"
ON*26  Thermostat  Touch the upper and
lower radiator hosesBoth hoses should be hot
CO-27
ON*17  Cooling fan  CONSULT-III Operating See trouble diagnosis for
DTC P1217 (EC-437
).
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 res- ervoir tank  Visual No overflow during driving
and idling CO-10, "
Changing Engine
Coolant"
OFF*410  Coolant return from res-
ervoir tank to radiator  Visual Should be initial level in
reservoir tank CO-10, "Changing Engine
Coolant"
OFF 11  Cylinder head  Straight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping) EM-101, "Removal and
Installation"
12  Cylinder block and pis-
tons  Visual No scuffing on cylinder
walls or piston EM-122
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TROUBLE DIAGNOSISEC-671
< SERVICE INFORMATION > [VK45DE]
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Fail-Safe ChartINFOID:0000000001326525
When the DTC listed below is detected, the EC
M enters fail-safe mode and the MIL lights up.
Priority Detected items (DTC)
1  U1000 U1001 CAN communication line  U1010 CAN communication
 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 posi tion sensor (PHASE)
 P0460 P0461 P0462 P0463 Fuel level sensor
 P0500 Vehicle speed sensor
 P0605 ECM
 P0643 Sensor power supply
 P0700 TCM
 P0705 Park/neutral position (PNP) switch
 P0850 Park/neutral position (PNP) switch
 P1610 - P1615 NATS
 P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor
2  P0031 P0032 P0051 P0052 Air fuel ratio (A/F) sensor 1 heater  P0037 P0038 P0057 P0058 Heated oxygen sensor 2 heater
 P0075 P0081 Intake valve timing control solenoid valve
 P0130 P0131 P0132 P0133 P0150 P0151 P0152 P0153 P2A00 P2A03 Air fuel ratio (A/F) sensor 1
 P0137 P0138 P0139 P0157 P0158 P0159 Heated oxygen sensor 2
 P0441 EVAP control system purge flow monitoring
 P0443 P0444 P0445 EVAP canister purge volume control solenoid valve
 P0447 P0448 EVAP canister vent control valve
 P0451 P0452 P0453 EVAP control system pressure sensor
 P0550 Power steering pressure sensor
 P0603 ECM power supply
 P0710 P0717 P0720 P0731 P0732 P0733 P0734 P0735 P0740 P0744 P0745 P1730 P1752 P1757 P1762 P1767
P1772 P1774 A/T related sensors, solenoid valves and switches
 P1140 P1145 Intake valve timing control position sensor
 P1217 Engine over temperature (OVERHEAT)
 P1805 Brake switch
 P2100 P2103 Throttle control motor relay
 P2101 Electric throttle control function
 P2118 Throttle control motor
3  P0011 P0021 Intake valve timing control  P0171 P0172 P0174 P0175 Fuel injection system function
 P0300 - P0308 Misfire
 P0420 P0430 Three way catalyst function
 P0442 P0456 EVAP co ntrol system (SMALL LEAK, VERY SMALL LEAK)
 P0455 EVAP control system (GROSS LEAK)
 P0506 P0507 Idle speed control system
 P1148 P1168 Closed loop control
 P1211 TCS control unit
 P1212 TCS communication line
 P1421 Cold start control
 P1564 ICC steering switch / ASCD steering switch
 P1568 ICC command value
 P1572 ICC brake switch / ASCD brake switch
 P1574 ICC vehicle speed sensor / ASCD vehicle speed sensor
 P1715 Turbine revolution sensor
 P1800 VIAS control solenoid valve
 P2119 Electric throttle control actuator
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TROUBLE DIAGNOSISEC-673
< SERVICE INFORMATION > [VK45DE]
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Symptom Matrix ChartINFOID:0000000001326526
SYSTEM — BASIC ENGINE CONTROL SYSTEM
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
Fuel Fuel pump circuit 11232 22 3 2 EC-1155
Fuel pressure regulator system 334444444 4EC-665
Fuel injector circuit 11232 22 2EM-190
Evaporative emission system 334444444 4EC-618
Air Positive crankcase ventilation sys-
tem 334444444 41
EC-629
Incorrect idle speed adjustment 1 1 1 1 1 EC-658
Electric throttle control actuator 112332222 2 2EC-1092,
EC-1102
IgnitionIncorrect ignition timing adjustment33111 11 1 EC-658
Ignition circuit 11222 22 2EC-1166
Main power supply and ground circuit 22333 33 23 EC-718
Mass air flow sensor circuit
1
12 2
222 2 EC-761,
EC-768
,
Engine coolant temperature sensor circuit
333
EC-779
,
EC-790
A/F sensor 1 circuit EC-798
,
EC-806
,
EC-814
,
EC-822
,
EC-1129
Throttle position sensor circuit
22EC-784
,
EC-889
,
EC-1041
,
EC-1043
,
E C - 111 6
Accelerator pedal position sensor circuit 3 2 1 EC-1009
,
EC-1104
,
E C - 111 0
,
EC-1122
Knock sensor circuit 2 3 EC-902
Crankshaft position sensor (POS) circuit 2 2EC-906
Camshaft position sensor (PHASE) circuit 3 2EC-911
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EC-674
< SERVICE INFORMATION >[VK45DE]
TROUBLE DIAGNOSIS
1 - 6: The numbers refer to the order of inspection.
(continued on next page)
SYSTEM — ENGINE MECHANICAL & OTHER
Vehicle speed signal circuit 2 3 3 3
EC-992
Power steering pressure sensor circuit 2 3 3EC-998
ECM 22333333333EC-1003,
EC-1007
Intake valve timing control solenoid valve cir-
cuit 32 13223 3
EC-754
PNP switch circuit 3 3 3 3 3 EC-1014
Refrigerant pressure sensor circuit 2 3 3 4EC-1177
Electrical load signal circuit 3EC-1147
Air conditioner circuit 223333333 3 2AT C - 3 2
VIAS control solenoid valve circuit 1EC-1080
ABS actuator and electric unit (control unit) 4EC-1028
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
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TROUBLE DIAGNOSISEC-675
< SERVICE INFORMATION > [VK45DE]
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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
Fuel Fuel tank 5
5 FL-10
Fuel piping 5 5 5 5 5 5
EM-190
Va p o r l o c k —
Valve deposit 5 555 55 5 —
Poor fuel (Heavy weight gasoline,
Low octane) —
Air Air duct
55555 5 EM-173
Air cleaner
EM-173
Air leakage from air duct
(Mass air flow sensor — electric
throttle control actuator)
5555 EM-173
Electric throttle control actuator
EM-175
Air leakage from intake manifold/
Collector/GasketEM-175
Cranking Battery
111111
11
SC-4
Generator circuit
SC-19
Starter circuit 3SC-8
Signal plate 6EM-241
PNP switch 4AT- 1 0 2
Engine Cylinder head
55555 55 5 EM-226
Cylinder head gasket 4 3
Cylinder block
66666 66 6 4
EM-241
Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Va l v e
mecha-
nism Timing chain
55555 55 5 EM-199
Camshaft
EM-211
Intake valve timing controlEM-199
Intake valve
3EM-199
Exhaust valve
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