2008 INFINITI FX35 Coolant Temperature Sensor

EC-294
< SERVICE INFORMATION >[VQ35DE]
DTC P0181 FTT SENSOR
DTC P0181 FTT SENSOR
Component DescriptionINFOID:0000000001326109
The fuel tank temperature (FTT)
sensor is used to detect the fuel
temperature inside the fuel tank. The sensor modifies a voltage sig-
nal from the ECM. The modified signal returns to the ECM as the
fuel temperature input. The sensor uses a thermistor which is sensi-
tive to the change in temperature. The electrical resistance of the
thermistor decreases as temperature increases.

*: This data is reference values and is measured between ECM terminal 107 (fuel
tank temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output
voltage. Doing so may result in damage to the ECM's transistor.
Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000001326110
DTC Confirmation ProcedureINFOID:0000000001326111
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 and wait at least 10 seconds.
2. Wait at least 10 seconds. If 1st trip DTC is detected, go to EC-296, "
Diagnosis Procedure".
If 1st trip DTC is not det ected, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-III.
4. Check “COOLAN TEMP/S” value. If “COOLAN TEMP/S” is less than 60 °C (140 °F), the result will be OK.
If “COOLAN TEMP/S” is above 60 °C (140 °F), go to the following step.
5. Cool engine down until “COOLAN TEMP/S” is less than 60 °C (140 °F).
6. Wait at least 10 seconds.
7. Check 1st trip DTC.
PBIB1572E
Fluid temperature °C ( °F) Voltage*
V Resistance
kΩ
20 (68) 3.5 2.3 - 2.7
50 (122) 2.2 0.79 - 0.90
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0181
0181 Fuel tank temperature
sensor circuit range/per-
formance Rationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signals
from engine coolant temperature sensor and in-
take air temperature sensor.  Harness or connectors
(Fuel tank temperature sensor circuit is
open or shorted)
 Fuel tank temperature sensor
 Unified meter and A/C amp.
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EC-348
< SERVICE INFORMATION >[VQ35DE]
DTC P0443 EVAP CANISTER PURGE VO
LUME CONTROL SOLENOID VALVE
DTC P0443 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VA LV E
DescriptionINFOID:0000000001326169
SYSTEM DESCRIPTION
*1: ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to the ECM through CAN communication line.
This system controls flow rate of fuel vapor from the EVAP canister. The opening of the vapor by-pass pas-
sage in the EVAP canister purge volume control sol enoid valve changes to control the flow rate. The EVAP
canister purge volume control solenoid valve repeats ON/O FF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engi ne control. The optimum value stored in the ECM is
determined by considering various engine conditions. When t he engine is operating, the flow rate of fuel vapor
from the EVAP canister is r egulated as the air flow changes.
COMPONENT DESCRIPTION
The EVAP canister purge volume control solenoid valve uses a ON/
OFF duty to control the flow rate of fuel vapor from the EVAP canis-
ter. The EVAP canister purge volume control solenoid valve is
moved by ON/OFF pulses from the ECM. The longer the ON pulse,
the greater the amount of fuel vapor that will flow through the valve.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001326170
Specification data are reference values.
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed*
1
EVAP canister
purge flow controlEVAP canister purge vol-
ume control solenoid valve
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Battery
Battery voltage*
1
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Air fuel ratio (A/F) sensor 1Density of oxygen in exhaust gas
(Mixture ratio fe
edback signal)
Fuel tank temperature sensor Fuel temperature in fuel tank
Wheel sensor Vehicle speed*
2
SEF337U
MONITOR ITEM CONDITION SPECIFICATION
PURG VOL C/V  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
No load Idle
(Accelerator pedal is not depressed
even slightly, after engine starting)
0%
2,000 rpm —
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DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VALVE
EC-355
< SERVICE INFORMATION > [VQ35DE]
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DTC P0444, P0445 EVAP CANISTER
PURGE VOLUME CONTROL SOLE-
NOID VALVE
DescriptionINFOID:0000000001326177
SYSTEM DESCRIPTION
*1: ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to the ECM through CAN communication line.
This system controls flow rate of fuel vapor from the EVAP canister. The opening of the vapor by-pass pas-
sage in the EVAP canister purge volume control solenoid valve changes to control the flow rate. The EVAP
canister purge volume control solenoid valve repeats ON/O FF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engi ne control. The optimum value stored in the ECM is
determined by considering various engine conditions. When t he engine is operating, the flow rate of fuel vapor
from the EVAP canister is regulated as the air flow changes.
COMPONENT DESCRIPTION
The EVAP canister purge volume control solenoid valve uses a ON/
OFF duty to control the flow rate of fuel vapor from the EVAP canis-
ter. The EVAP canister purge volume control solenoid valve is
moved by ON/OFF pulses from the ECM. The longer the ON pulse,
the greater the amount of fuel vapor that will flow through the valve.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001326178
Specification data are reference values.
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed*
1
EVAP canister
purge flow controlEVAP canister purge vol-
ume control solenoid valve
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Battery
Battery voltage*
1
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Air fuel ratio (A/F) sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel tank temperature sensor Fuel temperature in fuel tank
Wheel sensor Vehicle speed*
2
SEF337U
MONITOR ITEM CONDITION SPECIFICATION
PURG VOL C/V  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
 No load Idle
(Accelerator pedal is not depressed
even slightly, after engine starting)
0%
2,000 rpm —
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DTC P1217 ENGINE OVER TEMPERATUREEC-437
< SERVICE INFORMATION > [VQ35DE]
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DTC P1217 ENGINE OVER TEMPERATURE
DescriptionINFOID:0000000001326291
SYSTEM DESCRIPTION
NOTE:

If DTC P1217 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-146
.
 If DTC P1217 is displayed with DTC U1010, first performed the trouble diagnosis for DTC U1010.
Refer to EC-148
.
Cooling Fan Control
*1: The ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to ECM through CAN communication line.
The ECM controls the cooling fan corresponding to the vehicle speed, engine coolant temperature, refrigerant
pressure, and air conditioner ON signal. The control system has 4-step control [HIGH/MIDDLE/LOW/OFF].
Cooling Fan Operation
Cooling Fan Relay Operation
The ECM controls cooling fan relays in the IPDM E/R through CAN communication line.
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed*
1
Cooling fan
controlIPDM E/R
(Cooling fan relay)
Battery
Battery voltage*
1
Wheel sensor
Vehicle speed*2
Engine coolant temperature sensor Engine coolant temperature
Air conditioner switchAir conditioner ON signal*
2
Refrigerant pressure sensor Refrigerant pressure
PBIB3369E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
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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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SERVICE DATA AND SPECIFICATIONS (SDS)
EC-593
< SERVICE INFORMATION > [VQ35DE]
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SERVICE DATA AND SPECIFICATIONS (SDS)
Fuel PressureINFOID:0000000001326470
Idle Speed and Ignition TimingINFOID:0000000001326471
*1: Under the following conditions:
 Air conditioner switch: OFF
 Electric load: OFF (Lights, heater fan & rear window defogger)
 Steering wheel: Kept in straight-ahead position
Calculated Load ValueINFOID:0000000001326472
Mass Air Flow SensorINFOID:0000000001326473
*: Engine is warmed up to normal operating temperature and running under no load.
Intake Air Temperature SensorINFOID:0000000001326474
Engine Coolant Temperature SensorINFOID:0000000001326475
Air Fuel Ratio (A/F) Sensor 1 HeaterINFOID:0000000001326476
Heated Oxygen sensor 2 HeaterINFOID:0000000001326477
Fuel pressure at idling kPa (kg/cm2, psi)
Approximately 350 (3.57, 51)
Target idle speed
No load*1 (in P or N position) 650
±50 rpm
Air conditioner: ON In P or N position 700 rpm or more
Ignition timing In P or N position 15 ° ± 5 ° BTDC
Calculated load value% (Using CONSULT-III or GST)
At idle 5 - 35
At 2,500 rpm 5 - 35
Supply voltageBattery voltage (11 - 14V)
Output voltage at idle 1.0 - 1.2V*
Mass air flow (Using CONSULT-III or GST) 2.0 - 6.0 g·m/sec at idle*
7.0 - 20.0 g·m/sec at 2,500 rpm*
Temperature °C ( °F) Resistance k Ω
25 (77) 1.800 - 2.200
Temperature °C ( °F) Resistance k Ω
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
Resistance [at 25°C (77 °F)] 2.3 - 4.3 Ω
Resistance [at 25°C (77 °F)] 3.4 - 4.4 Ω
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EC-610
< SERVICE INFORMATION >[VK45DE]
ENGINE CONTROL SYSTEM
*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The amount of fuel injected from the fuel injector is
determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). T he amount of fuel injected is a program value in the
ECM memory. The program value is preset by engi ne operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from t he crankshaft position sensor (POS), camshaft position
sensor (PHASE) and the ma ss air flow sensor.
VARIOUS FUEL INJECTION I NCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compens ated to improve engine performance under various operat-
ing conditions as listed below.
 During warm-up
 When starting the engine
 During acceleration
 Hot-engine operation
 When selector lever is changed from N to D
 High-load, high-speed operation
 During deceleration
 During high engine speed operation
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector
Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch Gear position
Battery
Battery voltage*
3
Knock sensor Engine knocking condition
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit) VDC/TCS operation command*
2
Air conditioner switch Air conditioner operation
Wheel sensorVehicle speed*
2
PBIB3020E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

ENGINE CONTROL SYSTEMEC-611
< SERVICE INFORMATION > [VK45DE]
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The mixture ratio feedback system prov
ides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better r educe CO, HC and NOx emissions. This system uses A/F
sensor 1 in the exhaust manifold to monitor whether t he engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage si gnal. For more information about A/F sensor 1, refer to
EC-798
. This maintains the mixture ratio within the r ange of stoichiometric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the th ree way catalyst (manifold). Even if the switching
characteristics of A/F sensor 1 shift, the air-fuel rati o is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
 Deceleration and acceleration
 High-load, high-speed operation
 Malfunction of A/F sensor 1 or its circuit
 Insufficient activation of A/F sensor 1 at low engine coolant temperature
 High engine coolant temperature
 During warm-up
 After shifting from N to D
 When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM cont rols the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mi xture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value co mpared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensati on used to maintain the mixture ratio at its theoretical
value. The signal from A/F sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the the-
oretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an increase in
fuel volume if it is lean.
“Long term fuel trim” is overall fuel compensation ca rried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycl e according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all eight cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The eight fuel injectors will then receive the signals two times for each engine cycle.
This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
PBIB0122E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
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