2001 INFINITI QX4 ECU

Possible CauseNBEC0514IHarness or connector
(The vehicle speed sensor circuit is open or shorted.)
IVehicle speed sensor
DTC Confirmation ProcedureNBEC0245CAUTION:
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.
TESTING CONDITION:
Steps 1 and 2 may be conducted with the drive wheels lifted
in the shop or by driving the vehicle. If a road test is expected
to be easier, it is unnecessary to lift the vehicle.
SEF196Y
WITH CONSULT-IINBEC0245S011) Start engine (TCS switch ªOFFº).
2) Read ªVHCL SPEED SEº in ªDATA MONITORº mode with
CONSULT-II. The vehicle speed on CONSULT-II should
exceed 10 km/h (6 MPH) when rotating wheels with suitable
gear position.
If NG, go to ªDiagnostic Procedureº, EC-421.
If OK, go to following step.
3) Select ªDATA MONITORº mode with CONSULT-II.
4) Warm engine up to normal operating temperature.
5) Maintain the following conditions for at least 10 consecutive
seconds.
ENG SPEED 1,800 - 6,000 rpm
COOLAN TEMP/S More than 70ÉC (158ÉF)
B/FUEL SCHDL 5.5 - 14.0 msec
Selector lever Suitable position
PW/ST SIGNAL OFF
6) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-421.
Overall Function CheckNBEC0246Use this procedure to check the overall function of the vehicle
speed sensor circuit. During this check, a 1st trip DTC might not
be confirmed.
WITH GSTNBEC0246S011) Lift up drive wheels.
2) Start engine.
3) Read vehicle speed sensor signal in ªMODE 1º with GST.
The vehicle speed sensor on GST should be able to exceed
DTC P0500 VEHICLE SPEED SENSOR (VSS)
Possible Cause
EC-418

SEF197Y
SEF198Y
DTC Confirmation ProcedureNBEC0260CAUTION:
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-IINBEC0260S011) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch ªOFFº, wait at least 10 seconds and then
start engine.
3) Select ªCLSD THL/P SWº in ªDATA MONITORº mode.
If ªCLSD THL/P SWº is not available, go to step 5.
4) Check the signal under the following conditions.
Condition Signal indication
Throttle valve: Idle position ON
Throttle valve: Slightly open OFF
If the result is NG, go to ªDiagnostic Procedureº, EC-435.
If OK, go to following step.
5) Select ªDATA MONITORº mode with CONSULT-II.
6) Drive the vehicle for at least 5 consecutive seconds under the
following condition.
THRTL POS SEN More than 2.5V
VHCL SPEED SE More than 5 km/h (3 MPH)
Selector lever Suitable position
Driving locationDriving vehicle uphill (Increased engine load)
will help maintain the driving conditions
required for this test.
7) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-435.
SEF345X
Overall Function CheckNBEC0261Use this procedure to check the overall function of the closed
throttle position switch circuit. During this check, a 1st trip DTC
might not be confirmed.
WITH GSTNBEC0261S011) Start engine and warm it up to normal operating temperature.
2) Check the voltage between ECM terminal 56 (Closed throttle
position switch signal) and ground under the following condi-
tions.
At idle: Battery voltage
DTC P0510 CLOSED THROTTLE POSITION SWITCH
DTC Confirmation Procedure
EC-432

DTC Confirmation ProcedureNBEC0696CAUTION:
Always drive at a safe speed.
NOTE:
IIf both DTC P1111(B1), P1136 (B2) or P1140 (B1), P1145
(B2) and P1110 (B1), P1135 (B2) are displayed, perform
trouble diagnosis for ªDTC P1111(B1), P1136 (B2) or
P1140 (B1), P1145 (B2)º first. (See EC-451, 482.)
IIf ªDTC Confirmation Procedureº has been previously
conducted, always turn ignition switch ªOFFº and wait at
least 10 seconds before conducting the next test.
SEF353Z
PROCEDURE FOR MALFUNCTION ANBEC0696S01With CONSULT-IINBEC0696S01011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Maintain the following conditions for at least 10 consecutive
seconds.
ENG SPEED More than 2,000 rpm
COOLANT TEMPS More than 70ÉC (158ÉF)
Selector lever 1st position
Driving locationDriving vehicle uphill
(Increased engine load will help main-
tain the driving conditions required for
this test.)
4) Maintain the following conditions for at least 20 consecutive
seconds.
ENG SPEED Idle
COOLANT TEMPS More than 70ÉC (158ÉF)
Selector lever ªPº or ªNº position
5) If 1st trip DTC is detected, go to ªP1140, P1145 INTAKE
VALVE TIMING CONTROL POSITION SENSORº. Refer to
EC-482.
With GSTNBEC0696S0102Follow the procedure ªWith CONSULT-IIº above.
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DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
DTC Confirmation Procedure
EC-449

SEF353Z
PROCEDURE FOR MALFUNCTION B=NBEC0696S02With CONSULT-IINBEC0696S02011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Maintain the following conditions for at least 20 consecutive
seconds.
ENG SPEED2,000 - 3,000 rpm (A constant rotation
is maintained.)
COOLANT TEMPS 70 - 90ÉC (158 - 194ÉF)
Selector lever 1st or position
Driving location uphillDriving vehicle uphill
(Increased engine load will help main-
tain the driving conditions required for
this test.)
4) If 1st trip DTC is detected, go to ªP1140, P1145 INTAKE
VALVE TIMING CONTROL POSITION SENSORº. Refer to
EC-482.
With GSTNBEC0696S0202Follow the procedure ªWith CONSULT-IIº above.
DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
DTC Confirmation Procedure (Cont'd)
EC-450

If the check result is OK, perform the following step.
4) Let engine idle at least 5 minutes.
5) Maintain the following condition at least 50 consecutive sec-
onds.
B/FUEL SCHDL 3.6 msec or more
ENG SPEED 1,500 rpm or more
Selector lever Suitable position
VHCL SPEED SE More than 70 km/h (43 MPH)
During this test, P0130 and/or P0150 may be displayed on
CONSULT-II screen.
6) If DTC is detected, go to ªDiagnostic Procedureº, EC-492.
SEF308XB
Overall Function CheckNBEC0284Use this procedure to check the overall function of the closed loop
control. During this check, a DTC might not be confirmed.
WITH GSTNBEC0284S011) Start engine and warm it up to normal operating temperature.
2) Set voltmeter probes between ECM terminal 63 [Heated oxy-
gen sensor 1 (front) right bank signal] or 62 [Heated oxygen
sensor 1 (front) left bank signal] and engine ground.
3) Check the following with engine speed held at 2,000 rpm con-
stant under no-load.
IThe voltage should go above 0.70V at least once.
IThe voltage should go below 0.21V at least once.
4) If NG, go to ªDiagnostic Procedureº, EC-492.
Diagnostic ProcedureNBEC0285Perform trouble diagnosis for ªDTC P0133, P0153º, EC-218.
DTC P1148 (RIGHT BANK, -B1), P1168 (LEFT BANK, -B2) CLOSED LOOP
CONTROL
DTC Confirmation Procedure (Cont'd)
EC-492

place or refilling/draining fuel until the output voltage condition
of the ªFUEL LEVEL SEº meets within the range above and
leave the vehicle for more than 1 hour. Then start from step 1).
3) Turn ignition switch ªOFFº and wait at least 5 seconds.
4) Turn ignition switch ªONº.
5) Select ªEVAP VERY/SML LEAK P1441º of ªEVAPORATIVE
SYSTEMº in ªDTC WORK SUPPORTº mode with CONSULT-
II.
Follow the instruction displayed.
6) Make sure that ªOKº is displayed.
If ªNGº is displayed, refer to ªDiagnostic Procedureº, EC-529.
NOTE:
IIf the engine speed cannot be maintained within the range
displayed on CONSULT-II screen, go to ªBasic
inspectionº, EC-101.
IMake sure that EVAP hoses are connected to EVAP canis-
ter purge volume control solenoid valve properly.
OVERALL FUNCTION CHECKNBEC0317S05With GST
Use this procedure to check the overall function of the EVAP very
small leak function. During this check, a 1st trip DTC might not be
confirmed.
SEF462UA
CAUTION:
INever use compressed air, doing so may damage the
EVAP system.
IDo not start engine.
IDo not exceeded 4.12 kPa (0.042 kg/cm
2, 0.6 psi).
1) Attach the EVAP service port adapter securely to the EVAP
service port.
2) Set the pressure pump and a hose.
3) Also set a vacuum gauge via 3-way connector and a hose.
4) Turn ignition switch ªONº.
5) Connect GST and select mode 8.
6) Using mode 8 control the EVAP canister vent control valve
(close) and vacuum cut valve bypass valve (open).
7) Apply pressure and make sure the following conditions are
satisfied.
Pressure to be applied: 2.7 kPa (20 mmHg, 0.79 inHg)
Time to be waited after the pressure drawn in to the EVAP
system and the pressure to be dropped: 60 seconds and
the pressure should not be dropped more than 0.4 kPa (3
mmHg, 0.12 inHg)
If NG, go to diagnostic procedure, EC-529.
NOTE:
For more information, refer to GST instruction manual.
DTC P1441 EVAP CONTROL SYSTEM (VERY SMALL LEAK)
DTC Confirmation Procedure (Cont'd)
EC-528

5 INSTALL THE PRESSURE PUMP
To locate the EVAP leak, install EVAP service port adapter and pressure pump to EVAP service port securely.
SEF983Y
SEF916U
NOTE:
Improper installation of the EVAP service port adapter to the EVAP service port may cause leaking.
Models with CONSULT-II©GO TO 6.
Models without CON-
SULT-II©GO TO 7.
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DTC P1441 EVAP CONTROL SYSTEM (VERY SMALL LEAK)
Diagnostic Procedure (Cont'd)
EC-531

DTC Confirmation ProcedureNBEC0371CAUTION:
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.
SEF212Y
SEF213Y
WITH CONSULT-IINBEC0371S011) Turn ignition switch ªONº.
2) Select ªP/N POSI SWº in ªDATA MONITORº mode with CON-
SULT-II. Then check the ªP/N POSI SWº signal under the fol-
lowing conditions.
Position (Selector lever) Known-good signal
ªNº and ªPº position ON
Except the above position OFF
If NG, go to ªDiagnostic Procedureº, EC-608.
If OK, go to following step.
3) Select ªDATA MONITORº mode with CONSULT-II.
4) Start engine and warm it up to normal operating temperature.
5) Maintain the following conditions for at least 60 consecutive
seconds.
ENG SPEED 1,500 - 2,500 rpm
COOLAN TEMP/S More than 70ÉC (158ÉF)
B/FUEL SCHDL 3.6 - 12 msec
VHCL SPEED SE 70 - 100 km/h (43 - 62 MPH)
Selector lever Suitable position
6) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-608.
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DTC P1706 PARK/NEUTRAL POSITION (PNP) SWITCH
DTC Confirmation Procedure
EC-605