2001 INFINITI QX4 diagram

Wiring DiagramNBEC0344
MEC963C
DTC P1448 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (OPEN)
Wiring Diagram
EC-576

Wiring DiagramNBEC0640
MEC985C
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1464 FUEL LEVEL SENSOR CIRCUIT (GROUND SIGNAL)
Wiring Diagram
EC-583

Diagnostic Procedure=NBEC0641
1 CHECK FUEL LEVEL SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 59 and body ground. 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 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
1. Check the following.
IHarness connectors F27, M94
IHarness connectors M2, B1
IHarness for open between ECM and body ground
©Replace open circuit or short to power in harness or connectors.
3 CHECK FUEL LEVEL SENSOR
Refer to EL-108, ªFuel Level Sensor Unit Checkº.
OK or NG
OK©GO TO 4.
NG©Replace fuel level sensor unit.
4 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
OK or NG
©INSPECTION END
DTC P1464 FUEL LEVEL SENSOR CIRCUIT (GROUND SIGNAL)
Diagnostic Procedure
EC-584

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)
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
Description
EC-585

Wiring DiagramNBEC0351
MEC972C
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
Wiring Diagram
EC-587

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.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1490 VACUUM CUT VALVE BYPASS VALVE (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-589

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)
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1491 VACUUM CUT VALVE BYPASS VALVE
Description
EC-591

Wiring DiagramNBEC0359
MEC972C
DTC P1491 VACUUM CUT VALVE BYPASS VALVE
Wiring Diagram
EC-594