check engine INFINITI QX4 2001 Factory Service Manual

6 CHECK IGNITION SPARK
1. Turn ignition switch ªOFFº.
2. Disconnect ignition coil assembly from rocker cover.
3. Connect a known good spark plug to the ignition coil assembly.
4. Place end of spark plug against a suitable ground and crank engine.
5. Check for spark.
SEF575Q
OK or NG
OK©GO TO 7.
NG©Check ignition coil with power transistor and their circuit. Refer to EC-499.
7 CHECK INJECTOR
1. Turn ignition switch ªOFFº.
2. Remove injector assembly.
Refer to EC-41.
Keep fuel hose and all injectors connected to injector gallery.
3. Disconnect all ignition coil harness connectors.
4. Turn ignition switch ªONº.
Make sure fuel does not drip from injector.
OK or NG
OK (Does not drip.)©GO TO 8.
NG (Drips.)©Replace the injector(s) from which fuel is dripping.
8 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
Trouble is fixed.©INSPECTION END
Trouble is not fixed.©Replace warm-up three way catalyst.
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DTC P0420 (RIGHT BANK, -B1), P0430 (LEFT BANK, -B2) THREE WAY
CATALYST FUNCTION
Diagnostic Procedure (Cont'd)
EC-351

On Board Diagnosis LogicNBEC0218NOTE:
If DTC P0440 is displayed with P1448, perform trouble diagno-
sis for DTC P1448 first. (See EC-573.)
This diagnosis detects leaks in the EVAP purge line using engine
intake manifold vacuum.
If pressure does not increase, the ECM will check for leaks in the
line between the fuel tank and EVAP canister purge volume con-
trol solenoid valve, under the following ªVacuum testº conditions.
The vacuum cut valve bypass valve is opened to clear the line
between the fuel tank and the EVAP canister purge volume control
solenoid valve. The EVAP canister vent control valve will then be
closed to shut the EVAP purge line off. The EVAP canister purge
volume control solenoid valve is opened to depressurize the EVAP
purge line using intake manifold vacuum. After this occurs, the
EVAP canister purge volume control solenoid valve will be closed.
SEF373Z
Malfunction is detected when EVAP control system has a leak,
EVAP control system does not operate properly.
CAUTION:
IUse only a genuine NISSAN fuel filler cap as a replace-
ment. If an incorrect fuel filler cap is used, the MIL may
come on.
IIf the fuel filler cap is not tightened properly, the MIL may
come on.
IUse only a genuine NISSAN rubber tube as a replacement.
Possible CauseNBEC0510IIncorrect fuel tank vacuum relief valve
IIncorrect fuel filler cap used
IFuel filler cap remains open or fails to close.
IForeign matter caught in fuel filler cap.
ILeak is in line between intake manifold and EVAP canister
purge volume control solenoid valve.
IForeign matter caught in EVAP canister vent control valve.
IEVAP canister or fuel tank leaks
IEVAP purge line (pipe and rubber tube) leaks
DTC P0440 EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)
On Board Diagnosis Logic
EC-352

11 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 (With CONSULT-II)©GO TO 13.
OK (Without CONSULT-
II)©GO TO 14.
NG©GO TO 12.
12 DETECT MALFUNCTIONING PART
Check the following.
IEVAP canister for damage
IEVAP hose between EVAP canister and water separator for clogging or poor connection
©Repair hose or replace EVAP canister.
13 CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION
With CONSULT-II
1. Disconnect vacuum hose to EVAP canister purge volume control solenoid valve at EVAP service port.
2. Start engine.
3. Perform ªPURG VOL CONT/Vº in ªACTIVE TESTº mode.
4. Touch ªQuº on CONSULT-II screen to increase ªPURG VOL CONT/Vº opening to 100.0%.
5. Check vacuum hose for vacuum when revving engine up to 2,000 rpm.
SEF984Y
OK or NG
OK©GO TO 16.
NG©GO TO 15.
14 CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Stop engine.
3. Disconnect vacuum hose to EVAP canister purge volume control solenoid valve at EVAP service port.
4. Start engine and let it idle for at least 80 seconds.
5. Check vacuum hose for vacuum when revving engine up to 2,000 rpm.
Vacuum should exist.
OK or NG
OK©GO TO 17.
NG©GO TO 15.
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DTC P0440 EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)
Diagnostic Procedure (Cont'd)
EC-361

15 CHECK VACUUM HOSE
Check vacuum hoses for clogging or disconnection. Refer to ªVacuum Hose Drawingº, EC-26.
OK or NG
OK (With CONSULT-II)©GO TO 16.
OK (Without CONSULT-
II)©GO TO 17.
NG©Repair or reconnect the hose.
16 CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
With CONSULT-II
1. Start engine.
2. Perform ªPURG VOL CONT/Vº in ªACTIVE TESTº mode with CONSULT-II. Check that engine speed varies according
to the valve opening.
SEF985Y
OK or NG
OK©GO TO 18.
NG©GO TO 17.
DTC P0440 EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)
Diagnostic Procedure (Cont'd)
EC-362

18 CHECK ABSOLUTE PRESSURE SENSOR
1. Remove absolute pressure sensor with its harness connector connected.
SEF961Y
2. Remove hose from absolute pressure sensor.
3. Install a vacuum pump to absolute pressure sensor.
4. Turn ignition switch ªONº and check output voltage between ECM terminal 80 and engine ground under the following
conditions.
SEF300XA
CAUTION:
IAlways calibrate the vacuum pump gauge when using it.
IDo not apply below þ93.3 kPa (±700 mmHg, ±27.56 inHg) or over 101.3 kPa (760 mmHg, 29.92 inHg) of pressure.
OK or NG
OK©GO TO 19.
NG©Replace absolute pressure sensor.
19 CHECK FUEL TANK TEMPERATURE SENSOR
1. Remove fuel level sensor unit.
2. Check resistance between fuel level sensor unit and fuel pump terminals 1 and 2 by heating with hot water or heat gun
as shown in the figure.
SEF974Y
OK or NG
OK©GO TO 20.
NG©Replace fuel level sensor unit.
DTC P0440 EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)
Diagnostic Procedure (Cont'd)
EC-364

3 CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID 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 1 and EVAP canister purge volume control solenoid valve terminal 2.
Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK (With CONSULT-II)©GO TO 4.
OK (Without CONSULT-
II)©GO TO 5.
NG©Repair open circuit or short to ground and short to power in harness or connetors.
4 CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION
With CONSULT-II
1. Start engine.
2. Perform ªPURG VOL CONT/Vº in ªACTIVE TESTº mode with CONSULT-II. Check that engine speed varies according
to the valve opening.
SEF985Y
OK or NG
OK©GO TO 6.
NG©GO TO 5.
DTC P0443 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
(CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-372

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

Diagnostic ProcedureNBEC0241
1 CHECK RUBBER TUBE
1. Turn ignition switch ªOFFº.
2. Check rubber tube connected to the EVAP control system pressure sensor for clogging, vent, kink, disconnection or
improper connection.
SEF495R
OK or NG
OK©GO TO 2.
NG©Reconnect, repair or replace.
2 RETIGHTEN GROUND SCREWS
Loosen and retighten engine ground screws.
SEF959Y
©GO TO 3.
3 CHECK CONNECTOR
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check sensor harness connector for water.
Water should not exist.
OK or NG
OK©GO TO 4.
NG©Repair or replace harness connector.
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DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
Diagnostic Procedure
EC-385

4 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ªONº.
2. Check voltage between EVAP control system pressure sensor terminal 3 and ground with CONSULT-II or tester.
SEF992Y
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors B101, B43
IHarness connectors B1, M2 and M94, F27
IHarness for open or short between EVAP control system pressure sensor and ECM
©Repair harness or connectors.
6 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between EVAP control system pressure sensor terminal 1 and engine ground.
Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors B101, B43
IHarness connectors B1, M2 and M94, F27
IHarness for open between EVAP control system pressure sensor and ECM
IHarness for open between EVAP control system pressure sensor and TCM (Transmission Control Module)
©Repair open circuit or short to power in harness or connectors.
DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
Diagnostic Procedure (Cont'd)
EC-386

8 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND
SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 84 and EVAP control system pressure sensor terminal 2.
Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK (With CONSULT-II)©GO TO 10.
OK (Without CONSULT-
II)©GO TO 11.
NG©GO TO 9.
9 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors B101, B43
IHarness connectors B1, M2 and M94, F27
IHarness for open or short between ECM and EVAP control system pressure sensor
©Repair open circuit or short to ground or short to power in harness or connectors.
10 CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
With CONSULT-II
1. Start engine.
2. Perform ªPURG VOL CONT/Vº in ªACTIVE TESTº mode with CONSULT-II. Check that engine speed varies according
to the valve opening.
SEF985Y
OK or NG
OK©GO TO 12.
NG©GO TO 11.
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DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
Diagnostic Procedure (Cont'd)
EC-387