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Nissan Murano Z50 (2007 year). Manual - part 67

ENGINE CONTROL SYSTEM

EC-21

Revision: 2006 July

2007 Murano

ENGINE CONTROL SYSTEM

PFP:23710

System Diagram

NBS002YI

PBIB2307E

EC-22

ENGINE CONTROL SYSTEM

Revision: 2006 July

2007 Murano

Multiport Fuel Injection (MFI) System

NBS002YJ

INPUT/OUTPUT SIGNAL CHART

*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*2: This signals 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 shift 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*

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*

Power steering pressure sensor

Power steering operation

Heated oxygen sensor 2*

Density of oxygen in exhaust gas

Air conditioner switch

Air conditioner operation*

Wheel sensor

Vehicle speed*

ENGINE CONTROL SYSTEM

EC-23

Revision: 2006 July

2007 Murano

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 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-227, "DTC P0130, P0150 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 (manifold). Even if the switching
characteristics 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 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 controls the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mixture 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 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 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 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

EC-24

ENGINE CONTROL SYSTEM

Revision: 2006 July

2007 Murano

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 six cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The six 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.

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) System

NBS002YK

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 - 2 - 3 - 4 - 5 - 6
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 signal. Comput-
ing 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

SEF179U

Sensor

Input Signal to ECM

ECM function

Actuator

Crankshaft position sensor (POS)

Engine speed*

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

Knock sensor

Engine knocking

Park/neutral position (PNP) switch

Gear position

Battery

Battery voltage*

Wheel sensor

Vehicle speed*

ENGINE CONTROL SYSTEM

EC-25

Revision: 2006 July

2007 Murano

●

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)

NBS002YL

INPUT/OUTPUT SIGNAL CHART

*: This signal is sent to the ECM through CAN communication line.

SYSTEM DESCRIPTION

If the engine speed is above 1,800 rpm under no load (for example, the shift position is neutral and engine
speed over is 1,800 rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies
based on engine speed.
Fuel cut will be operated until the engine speed reaches 1,500 rpm, then fuel cut will be cancelled.

NOTE:
This function is different from deceleration control listed under “Multiport Fuel Injection (MFI) System”,

EC-22

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*

EC-26

AIR CONDITIONING CUT CONTROL

Revision: 2006 July

2007 Murano

AIR CONDITIONING CUT CONTROL

PFP:23710

Input/Output Signal Chart

NBS002YM

*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

NBS002YN

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

Air 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*

Engine coolant temperature sensor

Engine coolant temperature

Battery

Battery voltage*

Refrigerant pressure sensor

Refrigerant pressure

Power steering pressure sensor

Power steering operation

Wheel sensor

Vehicle speed*

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

EC-27

Revision: 2006 July

2007 Murano

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

PFP:18930

System Description

NBS002YO

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 indicator and SET indicator in combination meter. If any
malfunction 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 indicator 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 indicator in combination meter illuminates.)

ACCELERATE 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.

●

Shift lever is changed to N, P, R position.

●

Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed.

●

VDC/TCS system is operated.

●

CVT control system has a malfunction. Refer to

EC-531, "DTC P1700 CVT CONTROL SYSTEM"

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

Unified meter and A/C amp.

Vehicle speed*

TCM

Powertrain revolution*

EC-28

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

Revision: 2006 July

2007 Murano

COAST OPERATION

When the SET/COAST switch is pressed during cruise control driving, decrease vehicle set speed until the
switch is released. And then ASCD will keep the new set speed.

RESUME OPERATION

When the RESUME/ACCELERATE switch is pressed after cancel operation other than pressing MAIN switch
is performed, vehicle speed will return to last set speed. To resume vehicle set speed, vehicle condition must
meet following conditions.

●

Brake pedal is released.

●

CVT shift lever is in other than P and N positions.

●

Vehicle speed is greater than 40 km/h (25 MPH) and less than 144 km/h (89 MPH).

Component Description

NBS002YP

ASCD STEERING SWITCH

Refer to

EC-514

ASCD BRAKE SWITCH

Refer to

EC-521

and

EC-605

STOP LAMP SWITCH

Refer to

EC-521

EC-541

and

EC-605

ELECTRIC THROTTLE CONTROL ACTUATOR

Refer to

and

ASCD INDICATOR

Refer to

EC-612

CAN COMMUNICATION

EC-29

Revision: 2006 July

2007 Murano

CAN COMMUNICATION

PFP:23710

System Description

NBS002YQ

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
Refer to

LAN-50, "CAN Communication Signal Chart"

, about CAN communication for detail.

EC-30

EVAPORATIVE EMISSION SYSTEM

Revision: 2006 July

2007 Murano

EVAPORATIVE EMISSION SYSTEM

PFP:14950

Description

NBS002YR

SYSTEM DESCRIPTION

The evaporative emission system is used to reduce hydrocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplished by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into the EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not operating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume control solenoid valve is controlled by ECM. When the
engine operates, the flow rate of vapor controlled by EVAP canister purge volume control solenoid valve is
proportionally regulated as the air flow increases.
EVAP canister purge volume control solenoid valve also shuts off the vapor purge line during decelerating and
idling.

PBIB1631E

EVAPORATIVE EMISSION SYSTEM

EC-31

Revision: 2006 July

2007 Murano

EVAPORATIVE EMISSION LINE DRAWING

PBIB3191E

EC-32

EVAPORATIVE EMISSION SYSTEM

Revision: 2006 July

2007 Murano

PBIB1385E

EVAPORATIVE EMISSION SYSTEM

EC-33

Revision: 2006 July

2007 Murano

Component Inspection

NBS002YS

EVAP CANISTER

Check EVAP canister as follows:

Block port B .

Blow air into port A and check that it flows freely out of port C .

Release blocked port B .

Apply vacuum pressure to port B and check that vacuum pres-
sure exists at the ports A and C .

Block port A and B .

Apply pressure to port C and check that there is no leakage.

FUEL TANK VACUUM RELIEF VALVE (BUILT INTO FUEL FILLER CAP)

Wipe clean valve housing.

Check valve opening pressure and vacuum.

If out of specification, replace fuel filler cap as an assembly.

CAUTION:

Use only a genuine fuel filler cap as a replacement. If an incor-
rect fuel filler cap is used, the MIL may come on.

EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE

Refer to

EC-412

FUEL TANK TEMPERATURE SENSOR

Refer to

EC-335

EVAP CANISTER VENT CONTROL VALVE

Refer to

EC-418

EVAP CONTROL SYSTEM PRESSURE SENSOR

Refer to

EC-429

PBIB1044E

SEF445Y

Pressure:

15.3 - 20.0 kPa (0.156 - 0.204 kg/cm

, 2.22

- 2.90 psi)

Vacuum:

−

6.0 to

−

3.3 kPa (

−

0.061 to

−

0.034 kg/cm

−

0.87 to

−

0.48 psi)

SEF943S

EC-34

EVAPORATIVE EMISSION SYSTEM

Revision: 2006 July

2007 Murano

EVAP SERVICE PORT

Positive pressure is delivered to the EVAP system through the EVAP
service port. If fuel vapor leakage in the EVAP system occurs, use a
leak detector to locate the leak.

Removal and Installation

NBS002YT

EVAP CANISTER

Tighten EVAP canister as shown in the figure.

EVAP CANISTER VENT CONTROL VALVE

Turn EVAP canister vent control valve counterclockwise.

Remove the EVAP canister vent control valve.

Always reprece O-ring with a new one.

How to Detect Fuel Vapor Leakage

NBS002YU

CAUTION:

●

Never use compressed air or a high pressure pump.

●

Do not exceed 4.12 kPa (0.042 kg/cm

, 0.6 psi) of pressure in EVAP system.

NOTE:

●

Do not start engine.

●

Improper installation of EVAP service port adapter to the EVAP service port may cause a leak.

SEF462UA

PBIB1383E

PBIB1384E

EVAPORATIVE EMISSION SYSTEM

EC-35

Revision: 2006 July

2007 Murano

WITH CONSULT-II

Attach the EVAP service port adapter securely to the EVAP service port.

Also attach the pressure pump and hose to the EVAP service port adapter.

Turn ignition switch ON.

Select the “EVAP SYSTEM CLOSE” of “WORK SUPPORT
MODE” with CONSULT-II.

Touch “START”. A bar graph (Pressure indicating display) will
appear on the screen.

Apply positive pressure to the EVAP system until the pressure
indicator reaches the middle of the bar graph.

Remove EVAP service port adapter and hose with pressure
pump.

Locate the leak using a leak detector. Refer to

EC-31, "EVAPO-

RATIVE EMISSION LINE DRAWING"

WITHOUT CONSULT-II

Attach the EVAP service port adapter securely to the EVAP ser-
vice port.

Also attach the pressure pump with pressure gauge to the EVAP
service port adapter.

PEF838U

PEF917U

SEF200U

SEF462UA

EC-36

EVAPORATIVE EMISSION SYSTEM

Revision: 2006 July

2007 Murano

Apply battery voltage to the terminal of EVAP canister vent control valve to make a closed EVAP system.

To locate the leak, deliver positive pressure to the EVAP system until pressure gauge points reach 1.38 to
2.76 kPa (0.014 to 0.028 kg/cm

, 0.2 to 0.4 psi).

Remove EVAP service port adapter and hose with pressure pump.

Locate the leak using a leak detector. Refer to

EC-31, "EVAPORATIVE EMISSION LINE DRAWING"

PBIB1365E

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