2001 INFINITI QX4 Blower

IAir intake system
(Oil filler cap, oil level gauge, etc.)
IFuel pressure
IEngine compression
IThrottle valve
IEvaporative emission system
2) On air conditioner equipped models, checks should be carried out while the air conditioner is ªOFFº.
3) On automatic transmission equipped models, when checking idle rpm, ignition timing and mixture ratio,
checks should be carried out while shift lever is in ªNº position.
4) When measuring ªCOº percentage, insert probe more than 40 cm (15.7 in) into tail pipe.
5) Turn off headlamps, heater blower, rear defogger.
6) Keep front wheels pointed straight ahead.
7) Make the check after the cooling fan has stopped.
BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-44

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
25 W/G Tachometer[Engine is running]
IWarm-up condition
IIdle speed7-8VH
SEF579X
[Engine is running]
IWarm-up condition
IEngine speed is 2,500 rpm.7-8VH
SEF580X
26 L/BECM relay
(Self shutt-off)[Engine is running]
[Ignition switch ªOFFº]
IFor a few seconds after turning ignition switch
ªOFFº0 - 1.5V
[Ignition switch ªOFFº]
IA few seconds passed after turning ignition
switch ªOFFºBATTERY VOLTAGE
(11 - 14V)
27 LG Air conditioner relay[Engine is running]
IBoth A/C switch and blower switch are ªONº
(Compressor is operating).0 - 1.0V
[Engine is running]
IA/C switch is ªOFFº.BATTERY VOLTAGE
(11 - 14V)
28 R/L Fuel pump relay[Ignition switch ªONº]
IFor 1 second after turning ignition switch ªONº
[Engine is running]0 - 1.5V
[Ignition switch ªONº]
I1 second passed after turning ignition switch
ªONº.BATTERY VOLTAGE
(11 - 14V)
29 GSwirl control valve con-
trol solenoid valve[Engine is running]
IIdle speed
IEngine coolant temperature is between 15 to
50ÉC (59 to 122ÉF).0 - 1.0V
[Engine is running]
IIdle speed
IEngine coolant temperature is above 55ÉC
(131ÉF).BATTERY VOLTAGE
(11 - 14V)
38 OR MIL[Ignition switch ªONº]0 - 1.0V
[Engine is running]
IIdle speedBATTERY VOLTAGE
(11 - 14V)
39 G/WVacuum cut valve
bypass valve[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
40 G/YEVAP canister vent
control valve[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
ECM Terminals and Reference Value (Cont'd)
EC-130

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
42 B/Y Start signal[Ignition switch ªONº]Approximately 0V
[Ignition switch ªSTARTº]9 - 12V
43 R Ignition switch[Ignition switch ªOFFº]0V
[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
44 L PNP switch[Ignition switch ªONº]
IGear position is ªPº or ªNº.Approximately 0V
[Ignition switch ªONº]
IExcept the above gear positionBATTERY VOLTAGE
(11 - 14V)
45 B/RAir conditioner switch
signal[Engine is running]
IBoth A/C switch and blower switch are ªONº.Approximately 0V
[Engine is running]
IA/C switch is ªOFFº.Approximately 5V
47 R/BPower steering oil
pressure switch[Engine is running]
ISteering wheel is being turned.0 - 1.0V
[Engine is running]
ISteering wheel is not being turned.Approximately 5V
48 B ECM ground[Engine is running]
IIdle speedEngine ground
51 BR A/C cut signal[Engine is running]
IAir conditioner is operating.0 - 0.5V
52 PU Electrical load signal[Engine is running]
IRear window defogger: ON
IHi-beam headlamp: ONBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
IElectrical load: OFF0V
55 W/BSwirl control valve con-
trol vacuum check
switch[Engine is running]
IIdle speed
IEngine coolant temperature is between 15 to
50ÉC (59 to 122ÉF).Approximately 5V
[Engine is running]
IIdle speed
IEngine coolant temperature is above 55ÉC
(131ÉF).0 - 1.0V
56 OR/LThrottle position switch
(Closed position)[Engine is running]
IAccelerator pedal fully releasedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
IAccelerator pedal depressedApproximately 0V
57 B ECM ground[Engine is running]
IIdle speedEngine ground
58 B/P Sensors' ground[Engine is running]
IWarm-up condition
IIdle speedApproximately 0V
59 BFuel level sensor
ground[Engine is running]
IIdle speedApproximately 0V
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
ECM Terminals and Reference Value (Cont'd)
EC-131

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
71 OR/LHeated oxygen sensor
2 (rear) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
72 ORHeated oxygen sensor
2 (rear) (bank 1)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
73 B/PMass air flow sensor
ground[Engine is running]
IWarm-up condition
IIdle speedApproximately 0V
79 Y/GIntake valve timing
control position sen-
sors (RH)[Engine is running]
IWarm-up condition
IIdle speedApproximately 0.5V
SEF351Z
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.Approximatley 0.5V
SEF352Z
80 L/RAbsolute pressure sen-
sor[Ignition switch ªONº]Approximately 4.4V
81 W/PURefrigerant pressure
sensor[Engine is running]
IWarm-up condition
IBoth A/C switch and blower switch are ªONº.
(Compressor operates.)0.36 - 3.88V
82 WThrottle position sensor
signal output[Engine is running]
IWarm-up condition
IAccelerator pedal fully releasedApproximately 0.4V
[Ignition switch ªONº]
IAccelerator pedal fully depressedApproximately 4V
83 Y/PU Fuel level sensor[Ignition switch ªONº]Approximately 0 - 4.8V
Output voltage varies with
fuel level.
84 L/GEVAP control system
pressure sensor[Ignition switch ªONº]Approximately 3.4V
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
ECM Terminals and Reference Value (Cont'd)
EC-133

IIf P0440, P1440 and P1447 are not displayed on the screen,
go to the following step.
10) Select ªMODE 1º with GST.
IIf SRT of EVAP system is set, the result will be OK.
IIf SRT of EVAP system is not set, go to step 6.
Diagnostic ProcedureNBEC0220
1 CHECK FUEL FILLER CAP DESIGN
1. Turn ignition switch ªOFFº.
2. Check for genuine NISSAN fuel filler cap design.
SEF915U
OK or NG
OK©GO TO 2.
NG©Replace with genuine NISSAN fuel filler cap.
2 CHECK FUEL FILLER CAP INSTALLATION
Check that the cap is tightened properly by rotating the cap clockwise.
OK or NG
OK©GO TO 3.
NG©IOpen fuel filler cap, then clean cap and fuel filler neck threads using air blower.
IRetighten until ratcheting sound is heard.
3 CHECK FUEL FILLER CAP FUNCTION
Check for air releasing sound while opening the fuel filler cap.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
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DTC P0440 EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)
DTC Confirmation Procedure (Cont'd)
EC-355

20 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
1. Remove EVAP control system pressure sensor with its harness connector connected.
CAUTION:
INever apply force to the air hole protector of the sensor if equipped.
SEF799W
2. Remove hose from EVAP control system pressure sensor.
3. Turn ignition switch ªONº.
4. Use pump to apply vacuum and pressure to EVAP control system pressure sensor as shown in figure.
CAUTION:
IAlways calibrate the vacuum pump gauge when using it.
IDo not apply below þ20 kPa (þ150 mmHg, þ5.91 inHg) or over 20 kPa (150 mmHg, 5.91 inHg) of pressure.
5. Check input voltage between ECM terminal 84 and ground.
SEF342X
CAUTION:
IDiscard and EVAP control system pressure sensor which has been dropped from a height of more than 0.5m
(19.7in) onto a hard surface such as a concrete floor; use a new one.
OK or NG
OK©GO TO 21.
NG©Replace EVAP control system pressure sensor.
21 CHECK EVAP PURGE LINE
Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks or improper connection.
Refer to ªEvaporative Emission Systemº, EC-32.
OK or NG
OK©GO TO 22.
NG©Repair or reconnect the hose.
22 CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
©GO TO 23.
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DTC P0440 EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)
Diagnostic Procedure (Cont'd)
EC-365

6 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors B101, B43
IHarness connectors B1, M2 and M94, F27
IHarness for open or short between EVAP canister vent control valve and ECM
©Repair open circuit or short to ground or short to power in harness or connectors.
7 CHECK RUBBER TUBE FOR CLOGGING
1. Disconnect rubber tube connected to EVAP canister vent control valve.
2. Check the rubber tube for clogging.
OK or NG
OK©GO TO 8.
NG©Clean the rubber tube using an air blower.
8 CHECK EVAP CANISTER VENT CONTROL VALVE-I
1. Remove EVAP canister vent control valve from EVAP canister.
2. Check portionBof EVAP canister vent control valve for being rusted.
SEF337X
OK or NG
OK©GO TO 9.
NG©Replace EVAP canister vent control valve.
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DTC P0446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-379

9 CHECK EVAP CANISTER VENT CONTROL VALVE-II
With CONSULT-II
1. Reconnect harness connectors disconnected.
2. Turn ignition switch ªONº.
3. Perform ªVENT CONTROL/Vº in ªACTIVE TESTº mode.
4. Check air passage continuity and operation delay time.
SEF991Y
Without CONSULT-II
Check air passage continuity and operation delay time under the following conditions.
SEF339X
Make sure new O-ring is installed properly.
OK or NG
OK©GO TO 11.
NG©GO TO 10.
10 CHECK EVAP CANISTER VENT CONTROL VALVE-III
1. Clean the air passage (PortionAtoB) of EVAP canister vent control valve using an air blower.
2. Perform Test No. 9 again.
OK or NG
OK©GO TO 11.
NG©Replace EVAP canister vent control valve.
11 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P0446 EVAPORATIVE EMISSION (EVAP) CANISTER VENT CONTROL
VALVE (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-380