Ac system INFINITI QX4 2001 Factory Service Manual

23 CHECK FUEL LEVEL SENSOR
Refer to EL-108, ªFuel Level Sensor Unit Checkº.
OK or NG
OK©GO TO 24.
NG©Replace fuel level sensor unit.
24 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P1441 EVAP CONTROL SYSTEM (VERY SMALL LEAK)
Diagnostic Procedure (Cont'd)
EC-540

DescriptionNBEC0319SYSTEM DESCRIPTIONNBEC0319S01
Sensor Input Signal to ECMECM
functionActuator
Crankshaft position sensor (POS) Engine speed (POS signal)
EVAP can-
ister purge
flow controlEVAP 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 sensorsDensity 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 DESCRIPTIONNBEC0319S02The 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
NBEC0320Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
PURG VOL C/VIEngine: After warming up
IAir conditioner switch ªOFFº
IShift lever: ªNº
INo-loadIdle (Vehicle stopped) 0%
2,000 rpm Ð
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 ValueNBEC0678Specification 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
COLORITEM CONDITION DATA (DC Voltage)
1 L/YEVAP canister purge
volume control sole-
noid valve[Engine is running]
IIdle speedBATTERY VOLTAGE
(11 - 14V)
SEF994U
[Engine is running]
IEngine speed is about 2,000 rpm (More than 100
seconds after starting engine).BATTERY VOLTAGE
(11 - 14V)
SEF995U
On Board Diagnosis LogicNBEC0322Malfunction 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 CauseNBEC0588IEVAP control system pressure sensor
IEVAP canister purge volume control solenoid valve (The valve
is stuck open.)
IEVAP canister vent control valve
IEVAP canister
IHoses
(Hoses are connected incorrectly or clogged.)
DTC P1444 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
ECM Terminals and Reference Value
EC-542

4 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR HOSE
Check disconnection or improper connection of hose connected to EVAP control system pressure sensor.
SEF495R
OK or NG
OK©GO TO 5.
NG©Repair it.
5 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check connectors for water.
Water should not exist.
OK or NG
OK©GO TO 6.
NG©Replace EVAP control system pressure sensor.
DTC P1444 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Diagnostic Procedure (Cont'd)
EC-546

6 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
1. Remove EVAP control system pressure sensor with its harness connector connected.
CAUTION:
INever 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 ªONº.
4. Use pump to apply vacuum and pressure to EVAP control system pressure sensor as shown in figure.
CAUTION:
IAlways calibrate the vacuum pump gauge when using it.
IDo not apply below þ20 kPa (þ150 mmHg, þ5.91 inHg) or over 20 kPa (150 mmHg, 5.91 inHg) of pressure.
5. Check input voltage between ECM terminal 84 and ground.
SEF342X
CAUTION:
IDiscard and EVAP control system pressure sensor which has been dropped from a height of more than 0.5 m
(19.7 in) onto a hard surface such as a concrete floor; use a new one.
OK or NG
OK (With CONSULT-II)©GO TO 7.
OK (Without CONSULT-
II)©GO TO 8.
NG©Replace EVAP control system pressure sensor.
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
Diagnostic Procedure (Cont'd)
EC-547

SEF032W
SEF143S
Component DescriptionNBEC0326The EVAP canister vent control valve is located on the EVAP can-
ister and is used to seal the canister vent.
This solenoid valve responds to signals from the ECM. When the
ECM sends an ON signal, the coil in the solenoid valve is ener-
gized. A plunger will then move to seal the canister vent. The abil-
ity to seal the vent is necessary for the on board diagnosis of other
evaporative emission control system components.
This solenoid valve is used only for diagnosis, and usually remains
opened.
When the vent is closed, under normal purge conditions, the
evaporative emission control system is depressurized and allows
ªEVAP Control System (Small Leak)º diagnosis.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0327Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
VENT CONT/VIIgnition switch: ON OFF
ECM Terminals and Reference ValueNBEC0679Specification 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
COLORITEM CONDITION DATA (DC Voltage)
40 G/YEVAP canister vent
control valve[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
On Board Diagnosis LogicNBEC0329Malfunction is detected when EVAP canister vent control valve
remains closed under specified driving conditions.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CLOSE)
Component Description
EC-553

Possible CauseNBEC0589IEVAP canister vent control valve
IEVAP control system pressure sensor and the circuit
IBlocked rubber tube to EVAP canister vent control valve
IWater separator
IEVAP canister is saturated with water.
SEF201Y
DTC Confirmation ProcedureNBEC0330CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
WITH CONSULT-IINBEC0330S011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine.
4) Drive vehicle at a speed of approximately 80 km/h (50 MPH)
for a maximum of 15 minutes.
NOTE:
If a malfunction exists, NG result may be displayed quicker.
5) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-556.
WITH GSTNBEC0330S02Follow the procedure ªWITH CONSULT-IIº above.
DTC P1446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CLOSE)
Possible Cause
EC-554

5 CHECK EVAP CANISTER VENT CONTROL VALVE-III
1. Clean the air passage (PortionAtoB) of EVAP canister vent control valve using an air blower.
2. Perform the procedure 4 again.
OK or NG
OK©GO TO 6.
NG©Replace EVAP canister vent control valve.
6 CHECK IF EVAP CANISTER SATURATED WITH WATER
1. Remove EVAP canister with EVAP canister vent control valve attached.
2. Check if water will drain from the EVAP canister.
SEF596U
YesorNo
Ye s©GO TO 7.
No©GO TO 9.
7 CHECK EVAP CANISTER
Weigh the EVAP canister with the EVAP canister vent control valve attached.
The weight should be less than 1.8 kg (4.0 lb).
OK or NG
OK©GO TO 9.
NG©GO TO 8.
8 DETECT MALFUNCTIONING PART
Check the following.
IEVAP canister for damage
IEVAP hose between EVAP canister and water separator for clogging or poor connection
©Repair hose or replace EVAP canister.
9 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR HOSE
Check disconnection or improper connection of hose connected to EVAP control system pressure sensor.
OK or NG
OK©GO TO 10.
NG©Repair it.
DTC P1446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CLOSE)
Diagnostic Procedure (Cont'd)
EC-558

10 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR
1. Disconnect EVAP control system pressure sensor harness connector.
SEF495R
2. Check connectors for water.
Water should not exist.
OK or NG
OK©GO TO 11.
NG©Replace EVAP control system pressure sensor.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CLOSE)
Diagnostic Procedure (Cont'd)
EC-559

11 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
1. Remove EVAP control system pressure sensor with its harness connector connected.
CAUTION:
INever 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 ªONº.
4. Use pump to apply vacuum and pressure to EVAP control system pressure sensor as shown in figure.
CAUTION:
IAlways calibrate the vacuum pump gauge when using it.
IDo not apply below þ20 kPa (þ150 mmHg, þ5.91 inHg) or over 20 kPa (150 mmHg, 5.91 inHg) of pressure.
5. Check input voltage between ECM terminal 84 and ground.
SEF342X
CAUTION:
IDiscard and EVAP control system pressure sensor which has been dropped from a height of more than 0.5 m
(19.7 in) onto a hard surface such as a concrete floor; use a new one.
OK or NG
OK©GO TO 12.
NG©Replace EVAP control system pressure sensor.
12 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P1446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CLOSE)
Diagnostic Procedure (Cont'd)
EC-560