2001 INFINITI QX4 ignition

SEF032W
SEF143S
Component DescriptionNBEC0228The 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
NBEC0229Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
VENT CONT/VIIgnition switch: ON OFF
ECM Terminals and Reference ValueNBEC0667Specification 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 LogicNBEC0231Malfunction is detected when an improper voltage signal is sent to
ECM through EVAP canister vent control valve.
DTC P0446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CIRCUIT)
Component Description
EC-374

Possible CauseNBEC0512IHarness or connectors
(The valve circuit is open or shorted.)
IEVAP canister vent control valve
DTC Confirmation ProcedureNBEC0232NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm battery
voltage is more than 11V at idle.
SEF058Y
WITH CONSULT-IINBEC0232S011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait at least 8 seconds.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-377.
WITH GSTNBEC0232S02Follow the procedure ªWITH CONSULT-IIº above.
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DTC P0446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CIRCUIT)
Possible Cause
EC-375

Diagnostic ProcedureNBEC0234
1 INSPECTION START
1. Do you have CONSULT-II?
YesorNo
Ye s©GO TO 2.
No©GO TO 3.
2 CHECK EVAP CANISTER VENT CONTROL VALVE CIRCUIT
With CONSULT-II
1. Turn ignition switch ªOFFº and then turn ªONº.
2. Select ªVENT CONTROL/Vº in ªACTIVE TESTº mode with CONSULT-II.
3. Touch ªON/OFFº on CONSULT-II screen.
SEF989Y
4. Check for operating sound of the valve.
Clicking noise should be heard.
OK or NG
OK©GO TO 7.
NG©GO TO 3.
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DTC P0446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CIRCUIT)
Diagnostic Procedure
EC-377

3 CHECK EVAP CANISTER VENT CONTROL VALVE POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect EVAP canister vent control valve harness connector.
SEF143S
3. Turn ignition switch ªONº.
4. Check voltage between EVAP canister vent control valve terminal 2 and ground with CONSULT-II or tester.
SEF990Y
OK or NG
OK©GO TO 5.
NG©GO TO 4.
4 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M2, B1 and B43, B101
IFuse block (J/B) connector M10
I10A fuse
IHarness for open or short between EVAP canister vent control valve and fuse
©Repair harness or connectors.
5 CHECK EVAP CANISTER VENT CONTROL VALVE OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 40 and EVAP canister vent control valve terminal 1.
Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 7.
NG©GO TO 6.
DTC P0446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-378

9 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 11.
NG©GO TO 10.
10 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. 9 again.
OK or NG
OK©GO TO 11.
NG©Replace EVAP canister vent control valve.
11 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P0446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-380

SEF053V
SEF954S
Component DescriptionNBEC0235The EVAP control system pressure sensor detects pressure in the
purge line. The sensor output voltage to the ECM increases as
pressure increases. The EVAP control system pressure sensor is
not used to control the engine system. It is used only for on board
diagnosis.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0236Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
EVAP SYS PRESIIgnition switch: ON Approx. 3.4V
ECM Terminals and Reference ValueNBEC0668Specification 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)
58 B/P Sensors' ground[Engine is running]
IWarm-up condition
IIdle speedApproximately 0V
84 L/GEVAP control system
pressure sensor[Ignition switch ªONº]Approximately 3.4V
111 P/B Sensors' power supply[Ignition switch ªONº]Approximately 5V
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DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
Component Description
EC-381

On Board Diagnosis LogicNBEC0238Malfunction is detected when an improper voltage signal from
EVAP control system pressure sensor is sent to ECM.
Possible CauseNBEC0513IHarness or connectors
(The EVAP control system pressure sensor circuit is open or
shorted.)
IRubber hose to EVAP control system pressure sensor is
clogged, vent, kinked, disconnected or improper connection.
IEVAP control system pressure sensor
IEVAP canister vent control valve
IEVAP canister purge volume control solenoid valve
IEVAP canister
IRubber hose from EVAP canister vent control valve to water
separator
DTC Confirmation ProcedureNBEC0239NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
Always perform test at a temperature of 5ÉC (41ÉF) or more.
DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
On Board Diagnosis Logic
EC-382

SEF194Y
SEF340X
WITH CONSULT-IINBEC0239S011) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch ªOFFº and wait at least 10 seconds.
3) Turn ignition switch ªONº.
4) Select ªDATA MONITORº mode with CONSULT-II.
5) Make sure that ªFUEL T/TEMP SEº is more than 0ÉC (32ÉF).
6) Start engine and wait at least 20 seconds.
7) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-385.
WITH GSTNBEC0239S021) Start engine and warm it up to normal operating temperature.
2) Check that voltage between ECM terminal 92 (Fuel tank tem-
perature sensor signal) and ground is less than 4.2V.
3) Turn ignition switch ªOFFº and wait at least 10 seconds.
4) Start engine and wait at least 20 seconds.
5) Select ªMODE 7º with GST.
6) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-385.
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DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
DTC Confirmation Procedure (Cont'd)
EC-383