2001 INFINITI QX4 IDX

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.
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DTC P1446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CLOSE)
Diagnostic Procedure (Cont'd)
EC-559

System DescriptionNBEC0333NOTE:
If DTC P1447 is displayed with P0510, perform trouble diagnosis for DTC P0510 first. (See EC-431.)
SEF373Z
In this evaporative emission (EVAP) control system, purge flow occurs during non-closed throttle conditions.
Purge volume is related to air intake volume. Under normal purge conditions (non-closed throttle), the EVAP
canister purge volume control solenoid valve is open to admit purge flow. Purge flow exposes the EVAP con-
trol system pressure sensor to intake manifold vacuum.
On Board Diagnosis LogicNBEC0334Under normal conditions (non-closed throttle), sensor output volt-
age indicates if pressure drop and purge flow are adequate. If not,
a fault is determined.
Malfunction is detected when EVAP control system does not oper-
ate properly, EVAP control system has a leak between intake mani-
fold and EVAP control system pressure sensor.
Possible CauseNBEC0590IEVAP canister purge volume control solenoid valve stuck
closed
IEVAP control system pressure sensor and the circuit
ILoose, disconnected or improper connection of rubber tube
IBlocked rubber tube
ICracked EVAP canister
IEVAP canister purge volume control solenoid valve circuit
IClosed throttle position switch
IBlocked purge port
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DTC P1447 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PURGE
FLOW MONITORING
System Description
EC-561

SEF355X
Overall Function CheckNBEC0336Use this procedure to check the overall monitoring function of the
EVAP control system purge flow monitoring. During this check, a
1st trip DTC might not be confirmed.
WITH GSTNBEC0336S011) Lift up drive wheels.
2) Start engine (TCS switch ªOFFº) and warm it up to normal
operating temperature.
3) Turn ignition switch ªOFFº, wait at least 10 seconds.
4) Start engine and wait at least 70 seconds.
5) Set voltmeter probes to ECM terminals 84 (EVAP control sys-
tem pressure sensor signal) and ground.
6) Check EVAP control system pressure sensor value at idle
speed and note it.
7) Establish and maintain the following conditions for at least 1
minute.
Air conditioner switch ON
Steering wheel Fully turned
Headlamp switch ON
Rear window defogger switch ON
Engine speed Approx. 3,000 rpm
Gear position Any position other than ªPº, ªNº or ªRº
8) Verify that EVAP control system pressure sensor value stays
0.1V less than the value at idle speed (measured at step 6) for
at least 1 second.
9) If NG, go to ªDiagnostic Procedureº, EC-564.
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DTC P1447 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PURGE
FLOW MONITORING
Overall Function Check
EC-563

3 CHECK PURGE FLOW
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Stop engine.
3. Disconnect vacuum hose connected to EVAP canister purge volume control solenoid valve at EVAP service port and
install vacuum gauge.
SEF983Y
4. Start engine and let it idle for at least 80 seconds.
5. Check vacuum gauge indication when revving engine up to 2,000 rpm.
Vacuum should exist.
6. Release the accelerator pedal fully and let idle.
Vacuum should not exist.
OK or NG
OK©GO TO 7.
NG©GO TO 4.
4 CHECK EVAP PURGE LINE
1. Turn ignition switch ªOFFº.
2. Check EVAP purge line for improper connection or disconnection.
Refer to ªEVAPORATIVE EMISSION LINE DRAWINGº, EC-36.
OK or NG
OK (With CONSULT-II)©GO TO 5.
OK (Without CONSULT-
II)©GO TO 6.
NG©Repair it.
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DTC P1447 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PURGE
FLOW MONITORING
Diagnostic Procedure (Cont'd)
EC-565

7 CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
With CONSULT-II
Check air passage continuity of EVAP canister purge volume control solenoid valve under the following conditions.
SEF334X
Without CONSULT-II
Check air passage continuity of EVAP canister purge volume control solenoid valve under the following conditions.
SEF335X
OK or NG
OK©GO TO 8.
NG©Replace EVAP canister purge volume control solenoid valve.
8 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR HOSE
1. Turn ignition switch ªOFFº.
2. Check disconnection or improper connection of hose connected to EVAP control system pressure sensor.
OK or NG
OK©GO TO 9.
NG©Repair it.
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DTC P1447 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PURGE
FLOW MONITORING
Diagnostic Procedure (Cont'd)
EC-567

13 CHECK EVAP CANISTER VENT CONTROL VALVE-II
With CONSULT-II
1. Reconnect harness connectors disconnected.
2. Turn ignition switch ªONº.
3. Perform ªVENT CONTROL/Vº in ªACTIVE TESTº mode.
4. Check air passage continuity and operation delay time.
SEF991Y
Without CONSULT-II
Check air passage continuity and operation delay time under the following conditions.
SEF339X
Make sure new O-ring is installed properly.
OK or NG
OK©GO TO 15.
NG©GO TO 14.
14 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 Test No. 13 again.
OK or NG
OK (With CONSULT-II)©GO TO 16.
OK (Without CONSULT-
II)©GO TO 16.
NG©Replace EVAP canister vent control valve.
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DTC P1447 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PURGE
FLOW MONITORING
Diagnostic Procedure (Cont'd)
EC-569

16 CHECK THROTTLE POSITION SWITCH
1. Install all removed parts.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch ªOFFº.
4. Remove vacuum hose connected to throttle opener.
5. Connect suitable vacuum hose to vacuum pump and the throttle opener.
6. Apply vacuum [more than þ40.0 kPa (þ300 mmHg, þ11.81 inHg)] until the throttle drum becomes free from the rod of
the throttle opener.
SEF793W
7. Disconnect closed throttle position switch harness connector.
8. Check continuity between closed throttle position switch terminals 6 and 5 under the following conditions.
Resistance measurement must be made with throttle position switch installed in vehicle.
SEF998Y
OK or NG
OK©GO TO 18.
NG©GO TO 17.
17 ADJUST THROTTLE POSITION SWITCH
Check the following items. Refer to ªBasic Inspectionº, EC-101.
MTBL0470
Is it possible to adjust closed throttle position switch?
YesorNo
Ye s©GO TO 18.
No©Replace throttle position switch.
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DTC P1447 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PURGE
FLOW MONITORING
Diagnostic Procedure (Cont'd)
EC-571

SEF032W
SEF143S
Component DescriptionNBEC0338NOTE:
If DTC P1448 is displayed with P0440, perform trouble diagno-
sis for DTC P1448 first.
The 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
NBEC0339Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
VENT CONT/VIIgnition switch: ON OFF
ECM Terminals and Reference ValueNBEC0680Specification 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 LogicNBEC0341Malfunction is detected when EVAP canister vent control valve
remains opened under specified driving conditions.
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DTC P1448 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (OPEN)
Component Description
EC-573