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Infiniti Q45 (FY33). Manual - part 228

SEC050C

AEC783A

EVAP canister vent control valve

Check air passage continuity.

Perform “VENT CONTROL/V” in “ACTIVE TEST” mode with
CONSULT-II.

Condition

VENT CONTROL/V

Air passage continuity

between

and

OFF

Yes

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ OR ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Condition

Air passage continuity

between

and

12V direct current supply between ter-
minals

and

No supply

Yes

If NG or operation takes more than 1 second, clean valve using air
blower or replace as necessary.
If the portion

is rusted, replace EVAP canister vent control

valve.
Make sure new O-ring is installed properly.

SEF829T

Water separator

Check visually for insect nests in the water separator air inlet.

Check visually for cracks or flaws in the appearance.

Check visually for cracks or flaws in the hose.

Check that

and

are not clogged by blowing air into

with

, and then

plugged.

In case of NG in items 2 - 4, replace the parts.

NOTE:
Do not disassemble water separator.

IDX

TROUBLE DIAGNOSIS FOR DTC P1440

Evaporative Emission (EVAP) Control System
(Small Leak) (Positive Pressure) (Cont’d)

EC-441

SEF359W

Absolute pressure sensor

Remove absolute pressure sensor with its harness connector
connected.

Remove hose from absolute pressure sensor.

Turn ignition switch “ON” and check output voltage between
terminal

and ground.

The voltage should be 3.2 to 4.8V.

Use pump to apply vacuum of −26.7 kPa (−200 mmHg, −7.87
inHg) to absolute pressure sensor as shown in figure and
check the output voltage.
The voltage should be 1.0 to 1.4V lower than the value
measured in step 3.

CAUTION:

Always calibrate the vacuum pump gauge when using it.

Do not apply below −93.3 kPa (−700 mmHg, −27.56 inHg)
or over 101.3 kPa (760 mmHg, 29.92 inHg) of pressure.

If NG, replace absolute pressure sensor.

SEF767X

SEF768X

MEC488B

MAP/BARO switch solenoid valve

1. Start engine and warm it up to normal operating tem-

perature.

2. Perform “MAP/BARO SW/V” in “ACTIVE TEST” mode

with CONSULT-II.

3. Check the following.

Condition: At idle under no-load

CONSULT-II display

MAP/BARO SW/V

ABSOL PRES/SE (Voltage)

BARO

More than 2.6V

MAP

Less than the voltage at BARO

Time for voltage to change

MAP/BARO SW/V

Required time to switch

BARO to MAP

Less than 1 second

MAP to BARO

4. If NG, check solenoid valve as shown below.

1. Remove MAP/BARO switch solenoid valve.
2. Check air passage continuity.

Condition

Air passage

continuity

between

and

Air passage

continuity

between

and

12V direct current supply
between terminals

and

Yes

No supply

Yes

3. If NG or operation takes more than 1 second, replace

solenoid valve.

TROUBLE DIAGNOSIS FOR DTC P1440

Evaporative Emission (EVAP) Control System
(Small Leak) (Positive Pressure) (Cont’d)

EC-442

SEF405UA

Fuel tank temperature sensor

Check resistance by heating with hot water or heat gun as shown
in the figure.

Temperature °C (°F)

Resistance k

Ω

20 (68)

2.3 - 2.7

50 (122)

0.79 - 0.90

If NG, replace fuel tank temperature sensor.

IDX

TROUBLE DIAGNOSIS FOR DTC P1440

Evaporative Emission (EVAP) Control System
(Small Leak) (Positive Pressure) (Cont’d)

EC-443

Evaporative Emission (EVAP) Canister Purge
Volume Control Valve

SYSTEM DESCRIPTION

Camshaft position sensor

Engine speed

ECM

EVAP canister
purge volume
control valve

Mass air flow sensor

Amount of intake air

Engine coolant temperature sen-
sor

Engine coolant temperature

Ignition switch

Start signal

Throttle position sensor

Throttle position

Heated oxygen sensor 1 (front)

Density of oxygen in exhaust gas

(Mixture ratio feedback signal)

Fuel tank temperature sensor

Fuel temperature in fuel tank

Vehicle speed sensor

Vehicle speed

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 valve changes to control the flow rate. A built-in step motor
moves the valve in steps corresponding to the ECM output pulses. The opening of the valve varies for opti-
mum engine control. The optimum value stored in the ECM is determined by considering various engine con-
ditions. When the engine is operating, the flow rate of fuel vapor from the EVAP canister is regulated as the
air flow changes.

SEF249P

COMPONENT DESCRIPTION

The EVAP canister purge volume control valve uses a step motor
to control the flow rate of fuel vapor from the EVAP canister. This
motor has four winding phases. It operates according to the output
pulse signal of the ECM. Two windings are turned ON and OFF in
sequence. Each time an ON pulse is issued, the valve opens or
closes, changing the flow rate. When no change in the flow rate is
needed, the ECM does not issue the pulse signal. A certain volt-
age signal is issued so that the valve remains at that particular
opening.

TROUBLE DIAGNOSIS FOR DTC P1444

EC-444

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