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Before replacing ECM, perform “ECM Terminals and Refer-
ence Value” inspection and make s INFINITI FX35 2006 Service Manual PRECAUTIONS EC-25
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Before replacing ECM, perform “ECM Terminals and Refer-
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PRECAUTIONS EC-25
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Revision: 2006 December 2006 FX35/FX45
Before replacing ECM, perform “ECM Terminals and Refer-
ence Value” inspection and make sure ECM functions prop-
erly. Refer to EC-110, "
ECM Terminals and Reference Value"
.
Handle mass air flow sensor carefully to avoid damage.
Do not disassemble mass air flow sensor.
Do not clean mass air flow sensor with any type of deter-
gent.
Do not disassemble electric throttle control actuator.
Even a slight leak in the air intake system can cause seri-
ous incidents.
Do not shock or jar the camshaft position sensor (PHASE), crankshaft position sensor (POS).
After performing each TROUBLE DIAGNOSIS, perform DTC
Confirmation Procedure or Overall Function Check.
The DTC should not be displayed in the DTC Confirmation
Procedure if the repair is completed. The Overall Function
Check should be a good result if the repair is completed.
When measuring ECM signals with a circuit tester, never
allow the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.
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.
MEF040D
SEF217U
SEF348N
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EC-26
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PRECAUTIONS
Revision: 2006 December 2006 FX35/FX45
B1 indicates the bank 1, B2 indicates the bank 2 as shown
in the figure.
Do not operate fuel pump when there is no fuel in lines.
Tighten fuel hose clamps to the specified torque.
Do not depress accelerator pedal when starting.
Immediately after starting, do not rev up engine unneces-
sarily.
Do not rev up engine just prior to shutdown.
When installing C.B. ham radio or a mobile phone, be sure
to observe the following as it may adversely affect elec-
tronic control systems depending on installation location.
–Keep the antenna as far as possible from the electronic
control units.
–Keep the antenna feeder line more than 20 cm (8 in) away
from the harness of electronic controls.
Do not let them run parallel for a long distance.
–Adjust the antenna and feeder line so that the standing-
wave radio can be kept smaller.
–Be sure to ground the radio to vehicle body.
SEC893C
PBIB1569E
SEF709Y
SEF708Y
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PREPARATION EC-27
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Revision: 2006 December 2006 FX35/FX45
PREPARATIONPFP:00002
Special Service ToolsNBS003KZ
The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here. Tool number
(Kent-Moore No.)
Tool name Description
KV10117100
(J-36471-A)
Heated oxygen
sensor wrench Loosening or tightening heated oxygen sensor
with 22 mm (0.87 in) hexagon nut
KV10114400
(J-38365)
Heated oxygen
sensor wrench Loosening or tightening air fuel ratio (A/F) sensor
a: 22 mm (0.87 in)
(J-44321)
Fuel pressure gauge
kit Checking fuel pressure
(J-44321-6)
Fuel pressure adapter Connecting fuel pressure gauge to quick
connector type fuel lines.
(J-44626)
Air fuel ratio (A/F)
sensor wrench Loosening or tightening air fuel ratio (A/F) sensor
1
(J-45488)
Quick connector
release Remove fuel tube quick connectors in engine
room.
S-NT379
S-NT636
LEC642
LBIA0376E
LEM054
PBIC0198E
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EC-28
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PREPARATION
Revision: 2006 December 2006 FX35/FX45
KV109E0010
(J-46209)
Break-out box Measuring ECM signals with a circuit tester
KV109E0080
(J-45819)
Y-cable adapter Measuring ECM signals with a circuit tester
Tool number
(Kent-Moore No.)
Tool name Description
S-NT825
S-NT826
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Commercial Service ToolsNBS003L0
Tool name
(Kent-Moore No.) Description
Leak detector
i.e. INFINITI FX35 2006 Service Manual PREPARATION EC-29
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Commercial Service ToolsNBS003L0
Tool name
(Kent-Moore No.) Description
Leak detector
i.e.](/manual-img/42/57019/w960_57019-1412.png)
PREPARATION EC-29
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Revision: 2006 December 2006 FX35/FX45
Commercial Service ToolsNBS003L0
Tool name
(Kent-Moore No.) Description
Leak detector
i.e.: (J-41416) Locating 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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EC-30
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ENGINE CONTROL SYSTEM
Revision: 2006 December 2006 FX35/FX45
ENGINE CONTROL SYSTEMPFP:23710
System DiagramNBS003L1
PBIB2281E
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Multiport Fuel Injection (MFI) SystemNBS003L2
INPUT/OUTPUT SIGNAL CHART
*1: This sens INFINITI FX35 2006 Service Manual ENGINE CONTROL SYSTEM EC-31
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Multiport Fuel Injection (MFI) SystemNBS003L2
INPUT/OUTPUT SIGNAL CHART
*1: This sens](/manual-img/42/57019/w960_57019-1414.png)
ENGINE CONTROL SYSTEM EC-31
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Multiport Fuel Injection (MFI) SystemNBS003L2
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 both the crankshaft position sensor 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
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
Knock sensor Engine knocking condition
Battery Battery voltage*
3
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
Air conditioner switch Air conditioner operation*
2
Wheel sensorVehicle speed*2
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Revision: 2006 December 2006 FX35/FX45
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ra INFINITI FX35 2006 Service Manual EC-32
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ENGINE CONTROL SYSTEM
Revision: 2006 December 2006 FX35/FX45
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ra](/manual-img/42/57019/w960_57019-1415.png)
EC-32
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ENGINE CONTROL SYSTEM
Revision: 2006 December 2006 FX35/FX45
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 1 can then better reduce CO, HC and NOx emissions. This system uses air fuel ratio
(A/F) 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 air fuel
ratio (A/F) sensor 1, refer to EC-240, "
DTC P0131, P0151 A/F SENSOR 1" . 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 1. Even if the switching characteris-
tics of air fuel ratio (A/F) 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 air fuel ratio (A/F) sensor 1 or its circuit
Insufficient activation of air fuel ratio (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 air fuel ratio (A/F)
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., 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 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 air fuel ratio (A/F) sensor 1 indicates whether the mixture ratio is RICH or LEAN com-
pared 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.
PBIB3020E