2007 INFINITI M35 thermostat

DTC P0128 THERMOSTAT FUNCTION
EC-233
[VQ35DE]
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2007 April2007 M35/M45
Component InspectionNBS004W6
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 InstallationNBS004W7
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-31, "WATER OUTLET AND WATER PIPING" .
PBIB2005E
Temperature °C (°F) Resistance kΩ
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P

EC-500
[VQ35DE]
DTC P1217 ENGINE OVER TEMPERATURE
Revision: 2007 April2007 M35/M45
Cooling Fan Motor
Cooling fan motor receives cooling fan motor operating voltage from
cooling fan control module (1). The revolution speed of cooling fan
motor is controlled by duty cycle of the voltage.

: Vehicle front

Cooling fan motor-1 (2)

Cooling fan motor-2 (3)
CONSULT-II Reference Value in Data Monitor ModeNBS00533
Specification data are reference values.
On Board Diagnosis LogicNBS00534
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 CheckNBS00535
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.
PBIB3352E
MONITOR ITEM CONDITION SPECIFICATION
FA N DU T Y

Engine: Running 0 - 100%
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 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 control module

Cooling fan motor

Radiator hose

Radiator

Radiator cap

Water pump

Thermostat
For more information, refer to EC-507,
"Main 12 Causes of Overheating" .

EC-504
[VQ35DE]
DTC P1217 ENGINE OVER TEMPERATURE
Revision: 2007 April2007 M35/M45
Diagnostic ProcedureNBS00537
1. CHECK COOLING FAN OPERATION
With CONSULT-II
1. Turn ignition switch ON.
2. Perform “FAN DUTY CONTROL” in “ACTIVE TEST” mode with
CONSULT-II.
3. Make sure that cooling fan speed varies according to the per-
cent.
Without CONSULT-II
1. Perform IPDM E/R auto active test and check cooling fan motors
operation, refer to PG-23, "
Auto Active Test" .
2. Make sure that cooling fan operates.
OK or NG
OK >> GO TO 2.
NG >> GO TO 5.
2. CHECK COOLING SYSTEM FOR LEAK
Refer to CO-11, "
LEAK CHECK"
OK or NG
OK >> GO TO 3.
NG >> Check the following for leak.

Hose

Radiator

Water pump
3. CHECK COMPONENT PARTS
Check the following.

Radiator cap. Refer to CO-16, "Checking Radiator Cap" .

Thermostat. Refer to CO-29, "WATER INLET AND THERMOSTAT ASSEMBLY" .

Engine coolant temperature sensor. Refer to EC-218, "Component Inspection" .
OK or NG
OK >> GO TO 4.
NG >> Replace malfunctioning component.
4. CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to EC-507, "
Main 12 Causes of Overheating" .
>>INSPECTION END
PBIB2737E

EC-508
[VQ35DE]
DTC P1217 ENGINE OVER TEMPERATURE
Revision: 2007 April2007 M35/M45
*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" . ON*
25
Coolant leaks
Visual No leaksCO-11, "LEAK CHECK"
ON*26
Thermostat
Touch the upper and
lower radiator hosesBoth hoses should be hotCO-29, "WATER INLET
AND THERMOSTAT
ASSEMBLY"
ON*17
Cooling fan
CONSULT-II Operating See trouble diagnosis for
DTC P1217 (EC-499
).
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 idlingMA-15, "Changing
Engine Coolant"
OFF*410
Coolant return from
reservoir tank to radia-
tor
Visual Should be initial level in
reservoir tankMA-15, "Changing
Engine Coolant"
OFF 11
Cylinder head
Straight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)EM-102, "CYLINDER
HEAD"
12
Cylinder block and pis-
tons
Visual No scuffing on cylinder
walls or pistonEM-124, "CYLINDER
BLOCK"
Engine Step Inspection item Equipment Standard Reference page

EC-798
[VK45DE]
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
DTC Inspection Priority ChartNBS005AF
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:

If DTC U1000 or U1001 is displayed with other DTC, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-865, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .

If DTC U1010 is displayed with other DTC, first perform the trouble diagnosis for DTC U1010. Refer
to EC-868, "
DTC U1010 CAN COMMUNICATION" .
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 position 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

P1550 P1551 P1552 P1553 P1554 Battery current sensor

P1610 - P1615 NATS

P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor

EC-804
[VK45DE]
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
1 - 6: The numbers refer to the order of inspection.Cooling
Radiator/Hose/Radiator filler cap
55555 55 45CO-43
,
CO-47
Thermostat 5CO-55
Water pumpCO-53
Water galleryCO-38
Cooling fan
5CO-51
Coolant level (Low)/Contami-
nated coolantCO-40
IVIS (INFINITI Vehicle Immobilizer System —
NATS)11EC-755 or
BL-244
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-939
[VK45DE]
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2007 April2007 M35/M45
DTC P0125 ECT SENSORPFP:22630
Component DescriptionNBS005D8
NOTE:
If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or
P0118. Refer to EC-926, "
DTC P0117, P0118 ECT SENSOR" .
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.

*: This data is reference value and is 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 LogicNBS005D9
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 coolant
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-941
[VK45DE]
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2007 April2007 M35/M45
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-55, "
THERMOSTAT AND WATER CONTROL VALVE" .
4. CHECK INTERMITTENT INCIDENT
Refer to EC-857, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
Refer to EC-928, "
Wiring Diagram" .
>>INSPECTION END
Component InspectionNBS005DC
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 InstallationNBS005DD
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-55, "THERMOSTAT AND WATER CONTROL VALVE" .
PBIB2005E
Temperature°C (°F) Resistance kΩ
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P