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![INFINITI FX35 2005 Service Manual EC-720
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PREPARATION
Revision: 2005 July 2005 FX
Commercial Service ToolsABS007HD
Tool name
(Kent-Moore No.) Description
Leak detector
i.e.: (J-41416) Locating the EVAP leak
EVAP service INFINITI FX35 2005 Service Manual EC-720
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PREPARATION
Revision: 2005 July 2005 FX
Commercial Service ToolsABS007HD
Tool name
(Kent-Moore No.) Description
Leak detector
i.e.: (J-41416) Locating the EVAP leak
EVAP service](/manual-img/42/57020/w960_57020-2112.png)
EC-720
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PREPARATION
Revision: 2005 July 2005 FX
Commercial Service ToolsABS007HD
Tool name
(Kent-Moore No.) Description
Leak detector
i.e.: (J-41416) Locating the EVAP leak
EVAP service port
adapter
i.e.: (J-41413-OBD) Applying positive pressure through EVAP service
port
Fuel filler cap adapter
i.e.: (MLR-8382) Checking fuel tank vacuum relief valve opening
pressure
Socket wrench Removing and installing engine coolant temperature sensor
Oxygen sensor thread
cleaner
i.e.: (J-43897-18)
(J-43897-12) Reconditioning the exhaust system threads
before installing a new oxygen sensor. Use with
anti-seize lubricant shown below.
a: 18 mm diameter with pitch 1.5 mm for
Zirconia Oxygen Sensor
b: 12 mm diameter with pitch 1.25 mm for
Titania Oxygen Sensor
Anti-seize lubricant
i.e.: (Permatex
TM
133AR or equivalent
meeting MIL
specification MIL-A-
907) Lubricating oxygen sensor thread cleaning tool
when reconditioning exhaust system threads.
S-NT703
S-NT704
S-NT815
S-NT705
AEM488
S-NT779
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ENGINE CONTROL SYSTEM EC-721
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ENGINE CONTROL SYSTEMPFP:23710
System DiagramABS00E3X
PBIB2554E
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![INFINITI FX35 2005 Service Manual EC-722
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ENGINE CONTROL SYSTEM
Revision: 2005 July 2005 FX
Multiport Fuel Injection (MFI) SystemABS00E3Y
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under INFINITI FX35 2005 Service Manual EC-722
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ENGINE CONTROL SYSTEM
Revision: 2005 July 2005 FX
Multiport Fuel Injection (MFI) SystemABS00E3Y
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under](/manual-img/42/57020/w960_57020-2114.png)
EC-722
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ENGINE CONTROL SYSTEM
Revision: 2005 July 2005 FX
Multiport Fuel Injection (MFI) SystemABS00E3Y
INPUT/OUTPUT SIGNAL CHART
*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). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from the crankshaft position sensor (POS), camshaft position
sensor (PHASE) and the mass air flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated 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
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed*
3
Piston position
Fuel injection
& mixture ratio
control Fuel injector
Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Heated oxygen 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)*
2VDC/TCS operation command
Air conditioner switch*
2Air conditioner operation
Wheel sensor*
2Vehicle speed
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![INFINITI FX35 2005 Service Manual ENGINE CONTROL SYSTEM EC-723
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MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provide INFINITI FX35 2005 Service Manual ENGINE CONTROL SYSTEM EC-723
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MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provide](/manual-img/42/57020/w960_57020-2115.png)
ENGINE CONTROL SYSTEM EC-723
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MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better reduce CO, HC and NOx emissions. This system uses
heated oxygen sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The
ECM adjusts the injection pulse width according to the sensor voltage signal. For more information about
heated oxygen sensor 1, refer to EC-935
. This maintains the mixture ratio within the range 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 three way catalyst (manifold). Even if the switching
characteristics of heated oxygen sensor 1 shift, the air-fuel ratio 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 heated oxygen sensor 1 or its circuit
Insufficient activation of heated oxygen 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 heated oxygen
sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to
the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as orig-
inally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during operation (i.e., 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 compared 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 compensation used to maintain the mixture ratio at its theoretical
value. The signal from heated oxygen sensor 1 indicates whether the mixture ratio is RICH or LEAN compared
to the theoretical 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 carried 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.
PBIB0121E
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![INFINITI FX35 2005 Service Manual EC-724
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ENGINE CONTROL SYSTEM
Revision: 2005 July 2005 FX
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder du INFINITI FX35 2005 Service Manual EC-724
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ENGINE CONTROL SYSTEM
Revision: 2005 July 2005 FX
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder du](/manual-img/42/57020/w960_57020-2116.png)
EC-724
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ENGINE CONTROL SYSTEM
Revision: 2005 July 2005 FX
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycle 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 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.
FUEL SHUT-OFF
Fuel to each cylinder is cut off during deceleration, operation of the engine at excessively high speeds or oper-
ation of the vehicle at excessively high speeds.
Electronic Ignition (EI) SystemABS00E3Z
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
Firing order: 1 - 8 - 7 - 3 - 6 - 5 - 4 - 2
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the
engine. The ignition timing data is stored in the ECM.
The ECM receives information such as the injection pulse width and camshaft position sensor (PHASE) sig-
nal. Computing this information, ignition signals are transmitted to the power transistor.
During the following conditions, the ignition timing is revised by the ECM according to the other data stored in
the ECM.
At starting
During warm-up
At idle
At low battery voltage
PBIB0122E
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed*
2
Piston position
Ignition timing
control Power transistor
Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Battery Battery voltage*
2
Knock sensor Engine knocking
Park/neutral position (PNP) switch Gear position
Wheel sensor*
1Vehicle speed
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During acceleration
The knock sensor retard system is designed only for emergencies. The bas INFINITI FX35 2005 Service Manual ENGINE CONTROL SYSTEM EC-725
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During acceleration
The knock sensor retard system is designed only for emergencies. The bas](/manual-img/42/57020/w960_57020-2117.png)
ENGINE CONTROL SYSTEM EC-725
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During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
Fuel Cut Control (at No Load and High Engine Speed)ABS00E40
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
If the engine speed is above 1,400 rpm under no load (for example, the selector lever position is neutral and
engine speed is over 1,400 rpm) fuel will be cut off after some time. The exact time when the fuel is cut off var-
ies based on engine speed.
Fuel cut will be operated until the engine speed reaches 1,000 rpm, then fuel cut will be cancelled.
NOTE:
This function is different from deceleration control listed under Multiport Fuel Injection (MFI) System, EC-722
.
Sensor Input Signal to ECM ECM function Actuator
Park/neutral position (PNP) switch Neutral position
Fuel cut con-
trol Fuel injector
Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed
Wheel sensor* Vehicle speed
Page 2119 of 4731
![INFINITI FX35 2005 Service Manual EC-726
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AIR CONDITIONING CUT CONTROL
Revision: 2005 July 2005 FX
AIR CONDITIONING CUT CONTROLPFP:23710
Input/Output Signal ChartABS00E41
*1: This signal is sent to the ECM through CAN communic INFINITI FX35 2005 Service Manual EC-726
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AIR CONDITIONING CUT CONTROL
Revision: 2005 July 2005 FX
AIR CONDITIONING CUT CONTROLPFP:23710
Input/Output Signal ChartABS00E41
*1: This signal is sent to the ECM through CAN communic](/manual-img/42/57020/w960_57020-2118.png)
EC-726
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AIR CONDITIONING CUT CONTROL
Revision: 2005 July 2005 FX
AIR CONDITIONING CUT CONTROLPFP:23710
Input/Output Signal ChartABS00E41
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
System DescriptionABS00E42
This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.
When the accelerator pedal is fully depressed.
When cranking the engine.
At high engine speeds.
When the engine coolant temperature becomes excessively high.
When operating power steering during low engine speed or low vehicle speed.
When engine speed is excessively low.
When refrigerant pressure is excessively low or high.
Sensor Input Signal to ECM ECM function Actuator
Air conditioner switch*
1Air conditioner ON signal
Air conditioner
cut control Air conditioner relay
Accelerator pedal position sensor Accelerator pedal position
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed*
2
Engine coolant temperature sensor Engine coolant temperature
Battery Battery voltage*
2
Refrigerant pressure sensor Refrigerant pressure
Power steering pressure sensor Power steering operation
Wheel sensor*
1Vehicle speed
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![INFINITI FX35 2005 Service Manual AUTOMATIC SPEED CONTROL DEVICE (ASCD) EC-727
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)PFP:18930
System DescriptionABS00E43
INPU INFINITI FX35 2005 Service Manual AUTOMATIC SPEED CONTROL DEVICE (ASCD) EC-727
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)PFP:18930
System DescriptionABS00E43
INPU](/manual-img/42/57020/w960_57020-2119.png)
AUTOMATIC SPEED CONTROL DEVICE (ASCD) EC-727
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)PFP:18930
System DescriptionABS00E43
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line
BASIC ASCD SYSTEM
Refer to Owner's Manual for ASCD operating instructions.
Automatic Speed Control Device (ASCD) allows a driver to keep vehicle at predetermined constant speed
without depressing accelerator pedal. Driver can set vehicle speed in advance between approximately 40 km/
h (25 MPH) and 144 km/h (89 MPH).
ECM controls throttle angle of electric throttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE lamp and SET lamp in combination meter. If any malfunc-
tion occurs in ASCD system, it automatically deactivates control.
NOTE:
Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws.
SET OPERATION
Press MAIN switch. (The CRUISE lamp in combination meter illuminates.)
When vehicle speed reaches a desired speed between approximately 40 km/h (25 MPH) and 144 km/h (89
MPH), press SET/COAST switch. (Then SET lamp in combination meter illuminates.)
ACCEL OPERATION
If the RESUME/ACCELERATE switch is pressed during cruise control driving, increase the vehicle speed until
the switch is released or vehicle speed reaches maximum speed controlled by the system.
And then ASCD will keep the new set speed.
CANCEL OPERATION
When any of following conditions exist, cruise operation will be canceled.
CANCEL switch is pressed
More than 2 switches at ASCD steering switch are pressed at the same time (Set speed will be cleared)
Brake pedal is depressed
Selector lever is changed to N, P, R position
Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed
TCS system is operated
When the ECM detects any of the following conditions, the ECM will cancel the cruise operation and inform
the driver by blinking indicator lamp.
Engine coolant temperature is slightly higher than the normal operating temperature, CRUISE lamp may
blink slowly.
When the engine coolant temperature decreases to the normal operating temperature, CRUISE lamp will
stop blinking and the cruise operation will be able to work by pressing SET/COAST switch or RESUME/
ACCELERATE switch.
Malfunction for some self-diagnoses regarding ASCD control: SET lamp will blink quickly.
If MAIN switch is turned to OFF during ASCD is activated, all of ASCD operations will be canceled and vehicle
speed memory will be erased.
Sensor Input signal to ECM ECM function Actuator
ASCD brake switch Brake pedal operation
ASCD vehicle speed control Electric throttle control
actuator
Stop lamp switch Brake pedal operation
ASCD steering switch ASCD steering switch operation
Park/Neutral position (PNP)
switch Gear position
Wheel sensor* Vehicle speed
TCM* Powertrain revolution