Infiniti QX4 (R50). Manual — part 268
20
CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
1. Remove EVAP control system pressure sensor with its harness connector connected.
CAUTION:
I
Never apply force to the air hole protector of the sensor if equipped.
SEF799W
2. Remove hose from EVAP control system pressure sensor.
3. Turn ignition switch “ON”.
4. Use pump to apply vacuum and pressure to EVAP control system pressure sensor as shown in figure.
CAUTION:
I
Always calibrate the vacuum pump gauge when using it.
I
Do not apply below −20 kPa (−150 mmHg, −5.91 inHg) or over 20 kPa (150 mmHg, 5.91 inHg) of pressure.
5. Check input voltage between ECM terminal 84 and ground.
SEF342X
CAUTION:
I
Discard and EVAP control system pressure sensor which has been dropped from a height of more than 0.5m
(19.7in) onto a hard surface such as a concrete floor; use a new one.
OK or NG
OK
©
GO TO 21.
NG
©
Replace EVAP control system pressure sensor.
21
CHECK EVAP PURGE LINE
Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks or improper connection.
Refer to “Evaporative Emission System”, EC-32.
OK or NG
OK
©
GO TO 22.
NG
©
Repair or reconnect the hose.
22
CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
©
GO TO 23.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1441 EVAP CONTROL SYSTEM (VERY SMALL LEAK)
Diagnostic Procedure (Cont’d)
EC-539
23
CHECK FUEL LEVEL SENSOR
Refer to EL-108, “Fuel Level Sensor Unit Check”.
OK or NG
OK
©
GO TO 24.
NG
©
Replace fuel level sensor unit.
24
CHECK INTERMITTENT INCIDENT
Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-140.
©
INSPECTION END
DTC P1441 EVAP CONTROL SYSTEM (VERY SMALL LEAK)
Diagnostic Procedure (Cont’d)
EC-540
Description
NBEC0319
SYSTEM DESCRIPTION
NBEC0319S01
Sensor
Input Signal to ECM
ECM
function
Actuator
Crankshaft position sensor (POS)
Engine speed (POS signal)
EVAP can-
ister purge
flow control
EVAP canister purge volume
control solenoid valve
Crankshaft position sensor (REF)
Engine speed (REF signal)
Mass air flow sensor
Amount of intake air
Engine coolant temperature sensor
Engine coolant temperature
Ignition switch
Start signal
Throttle position sensor
Throttle position
Throttle position switch
Closed throttle position
Heated oxygen sensors
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 canis-
ter. The opening of the vapor by-pass passage in the EVAP canis-
ter purge volume control solenoid valve changes to control the flow
rate. The EVAP canister purge volume control solenoid valve
repeats ON/OFF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engine control.
The optimum value stored in the ECM is determined by consider-
ing various engine conditions. When the engine is operating, the
flow rate of fuel vapor from the EVAP canister is regulated as the
air flow changes.
SEF337U
COMPONENT DESCRIPTION
NBEC0319S02
The EVAP canister purge volume control solenoid valve uses a
ON/OFF duty to control the flow rate of fuel vapor from the EVAP
canister. The EVAP canister purge volume control solenoid valve
is moved by ON/OFF pulses from the ECM. The longer the ON
pulse, the greater the amount of fuel vapor that will flow through the
valve.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0320
Specification data are reference values.
MONITOR ITEM
CONDITION
SPECIFICATION
PURG VOL C/V
I
Engine: After warming up
I
Air conditioner switch “OFF”
I
Shift lever: “N”
I
No-load
Idle (Vehicle stopped)
0%
2,000 rpm
—
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1444 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Description
EC-541
ECM Terminals and Reference Value
NBEC0678
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM’s transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.
WIRE
COLOR
ITEM
CONDITION
DATA (DC Voltage)
1
L/Y
EVAP canister purge
volume control sole-
noid valve
[Engine is running]
I
Idle speed
BATTERY VOLTAGE
(11 - 14V)
SEF994U
[Engine is running]
I
Engine speed is about 2,000 rpm (More than 100
seconds after starting engine).
BATTERY VOLTAGE
(11 - 14V)
SEF995U
On Board Diagnosis Logic
NBEC0322
Malfunction is detected when the canister purge flow is detected
during the specified driving conditions, even when EVAP canister
purge volume control solenoid valve is completely closed.
Possible Cause
NBEC0588
I
EVAP control system pressure sensor
I
EVAP canister purge volume control solenoid valve (The valve
is stuck open.)
I
EVAP canister vent control valve
I
EVAP canister
I
Hoses
(Hoses are connected incorrectly or clogged.)
DTC P1444 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
ECM Terminals and Reference Value
EC-542
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