2001 INFINITI QX4 check engine

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