Vacuum cut INFINITI QX4 2001 Factory Owner's Manual

7 CHECK FOR EVAP LEAK
Without CONSULT-II
1. Turn ignition switch ªOFFº.
2. Apply 12 volts DC to EVAP canister vent control valve. The valve will close. (Continue to apply 12 volts until the end of
test.)
SEF598U
3. Apply 12 volts DC to vacuum cut valve bypass valve. The valve will open. (Continue to apply 12V until the end of test.)
SEF599U
4. Pressurize the EVAP line using pressure pump with 1.3 to 2.7 kPa (10 to 20 mmHg, 0.39 to 0.79 inHg), then remove
pump and EVAP service port adapter.
NOTE:
INever use compressed air or a high pressure pump.
IDo not exceed 4.12 kPa (0.042 kg/cm
2, 0.6 psi) of pressure in the system.
5. Using EVAP leak detector, locate the EVAP leak. For the leak detector, refer to the instruction manual for more details.
Refer to ªEVAPORATIVE EMISSION LINE DRAWINGº, EC-36.
SEF200U
OK or NG
OK©GO TO 8.
NG©Repair or replace.
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DTC P1441 EVAP CONTROL SYSTEM (VERY SMALL LEAK)
Diagnostic Procedure (Cont'd)
EC-533

Possible CauseNBEC0591IEVAP canister vent control valve
IEVAP control system pressure sensor and circuit
IBlocked rubber tube to EVAP canister vent control valve
IWater separator
IEVAP canister is saturated with water.
IVacuum cut valve
DTC Confirmation ProcedureNBEC0342NOTE:
IIf DTC P1448 is displayed with P0440 or P1440, perform
trouble diagnosis for DTC P1448 first.
IIf ªDTC Confirmation Procedureº has been previously
conducted, always turn ignition switch ªOFFº and wait at least
10 seconds before conducting the next test.
SEF565X
SEF566X
SEF567X
WITH CONSULT-IINBEC0342S01TESTING CONDITION:
IPerform ªDTC WORK SUPPORTº when the fuel level is
between 1/4 to 3/4 full and vehicle is placed on flat level
surface.
IOpen engine hood before conducting the following proce-
dure.
1) Turn ignition switch ªONº.
2) Turn ignition switch ªOFFº and wait at least 10 seconds.
3) Turn ignition switch ªONº and select ªDATA MONITORº mode
with CONSULT-II.
4) Make sure that the following conditions are met.
COOLAN TEMP/S 0 - 70ÉC (32 - 158ÉF)
INT/A TEMP SE 0 - 30ÉC (32 - 86ÉF)
5) Select ªEVAP SML LEAK P0440/P1440º of ªEVAPORATIVE
SYSTEMº in ªDTC WORK SUPPORTº mode with CONSULT-
II.
Follow the instruction displayed.
NOTE:
If the engine speed cannot be maintained within the range
displayed on the CONSULT-II screen, go to ªBasic Inspectionº,
EC-101.
6) Make sure that ªOKº is displayed.
If ªNGº is displayed, go to the following step.
NOTE:
Make sure that EVAP hoses are connected to EVAP canister
purge volume control solenoid valve properly.
7) Stop engine and wait at least 10 seconds, then turn ªONº.
8) Disconnect hose from water separator.
9) Select ªVENT CONTROL/Vº of ªACTIVE TESTº mode with
CONSULT-II.
10) Touch ªONº and ªOFFº alternately.
DTC P1448 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (OPEN)
Possible Cause
EC-574

5 CHECK VACUUM CUT VALVE
1. Turn ignition switch OFF.
2. Remove vacuum cut valve.
3. Check vacuum cut valve as follows:
SEF379Q
a. Plug portCandDwith fingers.
b. Apply vacuum to portAand check that there is no suction from portB.
c. Apply vacuum to portBand check that there is suction from portA.
d. Blow air in portBand check that there is a resistance to flow out of portA.
e. Open portCandD.
f. Blow air in portAcheck that air flows freely out of portC.
g. Blow air in portBcheck that air flows freely out of portD.
OK or NG
OK©GO TO 6.
NG©Replace vacuum cut 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.
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DTC P1448 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (OPEN)
Diagnostic Procedure (Cont'd)
EC-579

SEF485T
Description=NBEC0346COMPONENT DESCRIPTIONNBEC0346S01The vacuum cut valve and vacuum cut valve bypass valve are
installed in parallel on the EVAP purge line between the fuel tank
and the EVAP canister.
The vacuum cut valve prevents the intake manifold vacuum from
being applied to the fuel tank.
The vacuum cut valve bypass valve is a solenoid type valve and
generally remains closed. It opens only for on board diagnosis.
The vacuum cut valve bypass valve responds to signals from the
ECM. When the ECM sends an ON (ground) signal, the valve is
opened. The vacuum cut valve is then bypassed to apply intake
manifold vacuum to the fuel tank.
EVAPORATIVE EMISSION SYSTEM DIAGRAMNBEC0346S02
SEF373Z
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0347Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
VC/V BYPASS/VIIgnition switch: ON OFF
ECM Terminals and Reference ValueNBEC0681Specification 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)
39 G/WVacuum cut valve
bypass valve[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
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DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
Description
EC-585

On Board Diagnosis LogicNBEC0349Malfunction is detected when an improper voltage signal is sent to
ECM through vacuum cut valve bypass valve.
Possible CauseNBEC0592IHarness or connectors
(The vacuum cut valve bypass valve circuit is open or shorted.)
IVacuum cut valve bypass valve
DTC Confirmation ProcedureNBEC0350NOTE:
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 that bat-
tery voltage is more than 11V at idle speed.
SEF058Y
WITH CONSULT-IINBEC0350S011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait at least 5 seconds.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-588.
WITH GSTNBEC0350S02Follow the procedure ªWITH CONSULT-IIº above.
DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
On Board Diagnosis Logic
EC-586

Wiring DiagramNBEC0351
MEC972C
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DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
Wiring Diagram
EC-587

Diagnostic ProcedureNBEC0352
1 INSPECTION START
Do you have CONSULT-II?
YesorNo
Ye s©GO TO 2.
No©GO TO 3.
2 CHECK VACUUM CUT VALVE BYPASS VALVE CIRCUIT
With CONSULT-II
1. Turn ignition switch ªOFFº and then ªONº.
2. Select ªVC/V BYPASS/Vº in ªACTIVE TESTº mode with CONSULT-II.
3. Touch ªON/OFFº on CONSULT-II screen.
SEF014Z
4. Make sure that clicking sound is heard from the vacuum cut valve bypass valve.
OK or NG
OK©GO TO 7.
NG©GO TO 3.
DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
Diagnostic Procedure
EC-588

3 CHECK VACUUM CUT VALVE BYPASS VALUE POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect vacuum cut valve bypass valve harness connector.
SEF485T
3. Turn ignition switch ªONº.
4. Check voltage between vacuum cut valve bypass valve terminal 2 and ground with CONSULT-II or tester.
SEF015Z
OK or NG
OK©GO TO 5.
NG©GO TO 4.
4 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M2, B1
IFuse block (J/B) connector M10
IHarness connectors B43, B101 and B151, B152
I10A fuse
IHarness for open or short between vacuum cut valve bypass valve and fuse
©Repair harness or connectors.
5 CHECK VACUUM CUT VALVE BYPASS 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 39 and vacuum cut valve bypass 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.
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DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-589

6 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors B152, B151 and B101, B43
IHarness connectors B1, M2 and M94, F27
IHarness for open or short between vacuum cut valve bypass valve and ECM
©Repair open circuit or short to ground or short to power in harness or connectors.
7 CHECK VACUUM CUT VALVE BYPASS VALVE
With CONSULT-II
1. Reconnect harness disconnected connectors.
2. Turn ignition switch ON.
3. Perform ªVC/V BYPASS/Vº in ªACTIVE TESTº mode.
4. Check air passage continuity and operation delay time under the following conditions.
SEF016Z
Without CONSULT-II
Check air passage continuity and operation delay time under the following conditions.
SEF358X
OK or NG
OK©GO TO 8.
NG©Replace vacuum cut valve bypass valve.
8 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-590

SEF485T
DescriptionNBEC0353COMPONENT DESCRIPTIONNBEC0353S01The vacuum cut valve and vacuum cut valve bypass valve are
installed in parallel on the EVAP purge line between the fuel tank
and the EVAP canister.
The vacuum cut valve prevents the intake manifold vacuum from
being applied to the fuel tank.
The vacuum cut valve bypass valve is a solenoid type valve and
generally remains closed. It opens only for on board diagnosis.
The vacuum cut valve bypass valve responds to signals from the
ECM. When the ECM sends an ON (ground) signal, the valve is
opened. The vacuum cut valve is then bypassed to apply intake
manifold vacuum to the fuel tank.
EVAPORATIVE EMISSION SYSTEM DIAGRAMNBEC0353S02
SEF373Z
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0354Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
VC/V BYPASS/VIIgnition switch: ON OFF
ECM Terminals and Reference ValueNBEC0682Specification 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)
39 G/WVacuum cut valve
bypass valve[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
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DTC P1491 VACUUM CUT VALVE BYPASS VALVE
Description
EC-591