Nissan X-Trail 32. Manual - part 726

COMPONENT PARTS

EC-33

< SYSTEM DESCRIPTION >

[MR20DD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Electric throttle control actuator consists of throttle body, throttle valve, throttle control motor and throttle posi-
tion sensor.

THROTTLE CONTROL MOTOR RELAY

Power supply for the throttle control motor is provided to the ECM via throttle control motor relay. The throttle
control motor relay is ON/OFF controlled by the ECM. When the ignition switch is turned ON, the ECM sends
an ON signal to throttle control motor relay and battery voltage is provided to the ECM. When the ignition
switch is turned OFF, the ECM sends an OFF signal to throttle control motor relay and battery voltage is not
provided to the ECM.

THROTTLE CONTROL MOTOR

The throttle control motor is operated by the ECM and it opens and closes the throttle valve.

THROTTLE POSITION SENSOR

The throttle position sensor has two sensors. These sensors are a
kind of potentiometers which transform the throttle valve position into
output voltage, and emit the voltage signal to the ECM. In addition,
these sensors detect the opening and closing speed of the throttle
valve and feed the voltage signals to the ECM. The ECM judges the
current opening angle of the throttle valve from these signals and the
ECM controls the throttle control motor to make the throttle valve
opening angle properly in response to driving condition.

Ignition Coil With Power Transistor

INFOID:0000000010775007

Ignition coil with power transistor

The ignition signal from the ECM is sent to and amplified by the
power transistor. The power transistor turns ON and OFF the ignition
coil primary circuit. This ON/OFF operation induces the proper high
voltage in the coil secondary circuit.

JSBIA0270GB

PBIB0145E

JPBIA4613ZZ

EC-34

< SYSTEM DESCRIPTION >

[MR20DD]

COMPONENT PARTS

Fuel Injector

INFOID:0000000010775008

For the fuel injector, a high pressure fuel injector is used and this
enables a high-pressure fuel injection at a high voltage within a short
time. The ECM is equipped with an injector driver unit and actuates
the fuel injector at a high voltage (approximately 65 V at the maxi-
mum).

High Pressure Fuel Pump

INFOID:0000000010775009

• Balanced flow volume control type single cylinder high pressure fuel pump, which approximately equalize

the amount of injection and pump output, is adopted.

• The high pressure fuel pump is activated by the exhaust camshaft. ECM controls the high pressure fuel

pump control solenoid valve built into the high pressure fuel pump and adjusts the amount of discharge by
changing the suction timing of the low pressure fuel.

- Inflow process: Cam driven lowering plunger let the fuel from low pressure fuel pump induced into high pres-

sure fuel pump.

- Spill process: Although the cam driven plunger start moving upward, inflow check valve still at open position

due to the control solenoid valve, so the fuel is not pressurized and spilled out to low pressure fuel pump
side. By changing the amount of this spill out volume changes the amount of injection.

- Outflow process: When the control solenoid valve turns ON, the inflow check valve is closed, fuel is pressur-

ized and when the pressure exceeds certain point discharge check valve is pushed open to discharge fuel
into fuel rail. 

Operating Description

JPBIA4982ZZ

JSBIA0285GB

COMPONENT PARTS

EC-35

< SYSTEM DESCRIPTION >

[MR20DD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Operating Chart

Fuel Rail Pressure Sensor

INFOID:0000000010775010

The fuel rail pressure (FRP) sensor is placed to the fuel rail and
measures fuel pressure in the fuel rail. The sensor transmits voltage-
signal to the ECM. As the pressure increases, the voltage rises. The
ECM controls the fuel pressure in the fuel rail by operating high pres-
sure fuel pump. The ECM uses the signal from fuel rail pressure sen-
sor as a feedback signal.

Low Pressure Fuel Pump

INFOID:0000000010775011

The low pressure fuel pump is integrated with a fuel pressure 
regulator and a fuel filter. This pump is build into the fuel tank.

Mass Air Flow Sensor (With Intake Air Temperature Sensor)

INFOID:0000000010775012

MASS AIR FLOW SENSOR

JSBIA0286GB

JSBIA0291ZZ

JSBIA4496ZZ

EC-36

< SYSTEM DESCRIPTION >

[MR20DD]

COMPONENT PARTS

The mass air flow sensor

 is placed in the stream of intake air. It

measures the intake flow rate by measuring a part of the entire
intake flow. The MAF sensor controls the temperature of the heater
in sensing element to a certain amount. The temperature distribution
around the heater changes according to the increase in intake air
volume. The change is detected by a thermistor and the air volume
data is sent to ECM by the MAF sensor.

INTAKE AIR TEMPERATURE SENSOR

The intake air temperature sensor is built-into mass air flow sensor. The sensor detects intake air temperature
and transmits a signal to the ECM.
The temperature sensing unit uses a thermistor which is sensitive to the change in temperature.
<Reference data>

*: These data are reference values on the diagnosis tool.

Engine Coolant Temperature Sensor

INFOID:0000000010775013

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.

<Reference data>

*: These data are reference values and are measured between ECM terminals.

PBIA9559J

Intake air temperature

[

°

C (

°

F)]

Voltage

*

 (V)

Resistance (k

Ω

)

25 (77)

3.3

1.80 - 2.20

80 (176)

1.2

0.28 - 0.36

SEF012P

JPBIA5280ZZ

Engine coolant tem-

perature

[

°

C (

°

F)]

Voltage

*

 (V)

Resistance (k

Ω

)

−

10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.37 - 2.63

50 (122)

2.2

0.68 - 1.00

90 (194)

0.9

0.236 - 0.260

SEF012P