air condition INFINITI QX4 2001 Factory Repair Manual

MONITOR ITEM CONDITION SPECIFICATION
VHCL SPEED SEITurn drive wheels and compare speedometer indication with the CON-
SULT-II valueAlmost the same speed as
the CONSULT-II value
BATTERY VOLTIIgnition switch: ON (Engine stopped) 11 - 14V
THRTL POS SENIEngine: After warming up, idle
the engineThrottle valve: fully closed 0.15 - 0.85V
IEngine: After warming up
IIgnition switch: ON
(Engine stopped)Throttle valve: fully opened 3.5 - 4.7V
START SIGNALIIgnition switch: ON,START,ON OFF,ON,OFF
CLSD THL POS
CLSD THL/P SWIEngine: After warming up, idle
the engineThrottle valve: Idle position ON
Throttle valve: Slightly open OFF
AIR COND SIGIEngine: After warming up, idle
the engineAir conditioner switch: ªOFFº OFF
Air conditioner switch: ªONº
(Compressor operates.)ON
P/N POSI SWIIgnition switch: ONShift lever: ªPº or ªNº ON
Except above OFF
PW/ST SIGNALIEngine: After warming up, idle
the engineSteering wheel in neutral position
(forward direction)OFF
The steering wheel is turned ON
IGNITION SWIIgnition switch: ON,OFF,ON ON,OFF,ON
INJ PULSE-B2
INJ PULSE-B1IEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.4 - 3.2 msec
2,000 rpm 1.9 - 2.8 msec
B/FUEL SCHDLIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.0 - 3.2 msec
2,000 rpm 1.4 - 2.6 msec
IGN TIMINGIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 15ɱ5É BTDC
2,000 rpm More than 25É BTDC
IACV-AAC/VIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2 - 10 step
2,000 rpm Ð
PURG VOL C/VIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 0 %
2,000 rpm Ð
A/F ALPHA-B2
A/F ALPHA-B1IEngine: After warming upMaintaining engine speed at 2,000
rpm54 - 155%
EVAP SYS PRESIIgnition switch: ON Approx. 3.4V
AIR COND RLYIAir conditioner switch: OFF,ON OFF,ON
FUEL PUMP RLYIIgnition switch is turned to ON (Operates for 5 seconds)
IEngine running and crankingON
Except as shown above OFF
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
CONSULT-II Reference Value in Data Monitor Mode (Cont'd)
EC-123

MONITOR ITEM CONDITION SPECIFICATION
VENT CONT/VIIgnition switch: ON OFF
HO2S1 HTR (B1)
HO2S1 HTR (B2)IEngine speed: Below 3,600 rpm ON
IEngine speed: Above 3,600 rpm OFF
HO2S2 HTR (B1)
HO2S2 HTR (B2)IIgnition switch: ON (Engine stopped)
IEngine speed: Above 3,200 rpmOFF
IEngine speed: Below 3,200 rpm [After driving for 2 minutes at a speed
of 70 km/h (43 MPH) or more]ON
VC/V BYPASS/V Ignition switch: ON OFF
CAL/LD VALUEIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 14.0 - 33.0%
2,500 rpm 12.0 - 25.0%
ABSOL TH´P/SIEngine: After warming up Throttle valve: fully closed 0.0%
IEngine: After warming up
IIgnition switch: ON
(Engine stopped)Throttle valve: fully opened Approx. 80%
MASS AIRFLOWIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.0 - 6.0 g´m/s
2,500 rpm 7.0 - 20.0 g´m/s
ABSOL PRES/SEIIgnition switch: ON Approx. 4.4V
SWRL CONT S/VIEngine speed: IdleEngine coolant temperature is
between 15ÉC (59ÉF) to 50ÉC
(122ÉF).ON
Engine coolant temperature is above
55ÉC (131ÉF).OFF
SWL CON VC SWIEngine speed: Idle
IEngine coolant temperature is between 15ÉC (59ÉF) to 50ÉC (122ÉF).OFF
IEngine speed: Idle
IEngine coolant temperature is above 55ÉC (131ÉF).ON
INT/V TIM (B1)
INT/V TIM (B2)IEngine: After warming up
IShift lever ªNº
IQuickly depressed accelerator
pedal
INo-loadIdle 0É CA
2,000 rpm Approximately 12 - 18É CA
INT/V SOL (B1)
INT/V SOL (B2)IEngine: After warming up
IShift lever ªNº
IQuickly depressed accelerator
pedal
INo-loadIdle 0%
2,000 rpm Approximately 40%
Major Sensor Reference Graph in Data Monitor
Mode
NBEC0043The following are the major sensor reference graphs in ªDATA MONITORº mode.
THRTL POS SEN, ABSOL TH´P/S, CLSD THL POSNBEC0043S01Below is the data for ªTHRTL POS SENº, ªABSOL TH´P/Sº and ªCLSD THL POSº when depressing the accel-
erator pedal with the ignition switch ªONº.
The signal of ªTHRTL POS SENº and ªABSOL TH´P/Sº should rise gradually without any intermittent drop or
rise after ªCLSD THL POSº is changed from ªONº to ªOFFº.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
CONSULT-II Reference Value in Data Monitor Mode (Cont'd)
EC-124

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)
61 OR Mass air flow sensor[Engine is running]
IWarm-up condition
IIdle speed1.2 - 1.8V
[Engine is running]
IWarm-up condition
IEngine speed is 2,500 rpm.1.6 - 2.2V
62 G/BHeated oxygen sensor
1 (front) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V (Peri-
odically change)
SEF059V
63 GHeated oxygen sensor
1 (front) (bank 1)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V (Peri-
odically change)
SEF059V
64 Y/PUIntake air temperature
sensor[Engine is running]Approximately 0 - 4.8V
Output voltage varies with
intake air temperature.
65
75LG
LGCrankshaft position
sensor (REF)[Engine is running]
IWarm-up condition
IIdle speedApproximately 2.3VH
(AC voltage)
SEF581X
66
76L
LCamshaft position sen-
sor (PHASE)[Engine is running]
IWarm-up condition
IIdle speedApproximately 4.2VH
(AC voltage)
SEF582X
12
67W/RPower supply for ECM
(Buck-up)[Ignition switch ªOFFº]BATTERY VOLTAGE
(11 - 14V)
70 LG/REngine coolant tem-
perature sensor[Engine is running]Approximately 0 - 4.8V
Output voltage varies with
engine coolant temperature.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
ECM Terminals and Reference Value (Cont'd)
EC-132

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

DescriptionNBEC0717The specification (SP) value indicates the tolerance of the value that is displayed in ªDATA MONITOR (SPEC)º
mode of CONSULT-II during normal operation of the Engine Control System. When the value in ªDATA MONI-
TOR (SPEC)º mode is within the SP value, the Engine Control System is confirmed OK. When the value in
ªDATA MONITOR (SPEC)º mode is NOT within the SP value, the Engine Control System may have one or
more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not light the
MIL.
The SP value will be displayed for the following three items:
IB/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board cor-
rection)
IA/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)
IMAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing ConditionNBEC0718IVehicle driven distance: More than 5,000 km (3,100 miles)
IBarometric pressure: 101.3 kPa (760.0 mmHg, 29.92 inHg)±3 kPa (22.5 mmHg, 0.89 inHg)
IAtmospheric temperature: 20 - 30ÉC (68 - 86ÉF)
IEngine coolant temperature: 75 - 95ÉC (167 - 203ÉF)
ITransmission: Warmed-up*1
IElectrical load: Not applied*2
IEngine speed: Idle
*1: For A/T models, after the engine is warmed up to normal operating temperature, drive vehicle until ªFLUID
TEMP SEº (A/T fluid temperature sensor signal) indicates less than 0.9V.
*2: Rear window defogger switch, air conditioner switch, lighting switch are ªOFFº. Cooling fans are not oper-
ating. Steering wheel is straight ahead.
SEF601Z
Inspection ProcedureNBEC0719NOTE:
Perform ªDATA MONITOR (SPEC)º mode in maximum scale dis-
play.
1. Perform ªBasic Inspectionº, EC-101.
2. Confirm that the testing conditions indicated above are met.
3. Select ªB/FUEL SCHDLº, ªA/F ALPHA-B1º, ªA/F ALPHA-B2º
and ªMAS A/F SE-B1º in ªDATA MONITOR (SPEC)º mode with
CONSULT-II.
4. Make sure that monitor items are within the SP value.
5. If NG, go to ªDiagnostic Procedureº, EC-137.
TROUBLE DIAGNOSIS Ð SPECIFICATION VALUE
Description
EC-136

DescriptionNBEC0045Intermittent incidents (I/I) may occur. In many cases, the problem resolves itself (the part or circuit function
returns to normal without intervention). It is important to realize that the symptoms described in the custom-
er's complaint often do not recur on (1st trip) DTC visits. Realize also that the most frequent cause of I/I
occurrences is poor electrical connections. Because of this, the conditions under which the incident occurred
may not be clear. Therefore, circuit checks made as part of the standard diagnostic procedure may not indi-
cate the specific problem area.
COMMON I/I REPORT SITUATIONSNBEC0045S01
STEP in Work Flow Situation
II The CONSULT-II is used. The SELF-DIAG RESULTS screen shows time data other than ª0º or ª[1t]º.
III The symptom described by the customer does not recur.
IV (1st trip) DTC does not appear during the DTC Confirmation Procedure.
VI The Diagnostic Procedure for PXXXX does not indicate the problem area.
Diagnostic ProcedureNBEC0046
1 INSPECTION START
Erase (1st trip) DTCs. Refer to ªHOW TO ERASE EMISSION Ð RELATED INFORMATIONº, EC-72.
©GO TO 2.
2 CHECK GROUND TERMINALS
Check ground terminals for corroding or loose connection.
Refer to GI-30, ªGROUND INSPECTIONº.
OK or NG
OK©GO TO 3.
NG©Repair or replace.
3 SEARCH FOR ELECTRICAL INCIDENT
Perform GI-36, ªIncident Simulation Testsº.
OK or NG
OK©GO TO 4.
NG©Repair or replace.
4 CHECK CONNECTOR TERMINALS
Refer to GI-27, ªHow to Check Enlarged Contact Spring of Terminalº.
OK or NG
OK©INSPECTION END
NG©Repair or replace connector.
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT
Description
EC-140

SEF958Y
Component DescriptionNBEC0050The mass air flow sensor is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. It consists of a hot film that is supplied with electric
current from the ECM. The temperature of the hot film is controlled
by the ECM a certain amount. The heat generated by the hot film
is reduced as the intake air flows around it. The more air, the
greater the heat loss.
Therefore, the ECM must supply more electric current to maintain
the temperature of the hot film as air flow increases. The ECM
detects the air flow by means of this current change.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0051Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE-B1IEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 1.2 - 1.8V
2,500 rpm 1.6 - 2.2V
CAL/LD VALUE dittoIdle 14.0 - 33.0%
2,500 rpm 12.0 - 25.0%
MASS AIRFLOW dittoIdle 2.0 - 6.0 g´m/s
2,500 rpm 7.0 - 20.0 g´m/s
ECM Terminals and Reference ValueNBEC0649Specification 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)
61 OR Mass air flow sensor[Engine is running]
IWarm-up condition
IIdle speed1.2 - 1.8V
[Engine is running]
IWarm-up condition
IEngine speed is 2,500 rpm.1.6 - 2.2V
73 B/PMass air flow sensor
ground[Engine is running]
IWarm-up condition
IIdle speedApproximately 0V
111 P/B Sensors' power supply[Ignition switch ªONº]Approximately 5V
DTC P0100 MASS AIR FLOW SENSOR (MAFS)
Component Description
EC-150

On Board Diagnosis LogicNBEC0053Malfunction is detected when
(Malfunction A)an excessively high voltage from the sensor is
sent to ECM when engine is not running,
(Malfunction B)an excessively low voltage from the sensor is sent
to ECM when engine is running,
(Malfunction C)a high voltage from the sensor is sent to ECM
under light load driving condition,
(Malfunction D)a low voltage from the sensor is sent to ECM
under heavy load driving condition,
(Malfunction E)a voltage from the sensor is constantly approx.
1.0V when engine is running.
FAIL-SAFE MODENBEC0053S02When the malfunction B is detected, the ECM enters fail-safe mode
and the MIL lights up.
Detected items Engine operating condition in fail-safe mode
Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
Possible CauseNBEC0426MALFUNCTION A OR CNBEC0426S01IHarness or connectors
(The sensor circuit is open or shorted.)
IMass air flow sensor
MALFUNCTION B, D OR ENBEC0426S02IHarness or connectors
(The sensor circuit is open or shorted.)
IIntake air leaks
IMass air flow sensor
DTC Confirmation ProcedureNBEC0054Perform ªPROCEDURE FOR MALFUNCTION Aº first.
If the 1st trip DTC cannot be confirmed, perform ªPROCE-
DURE FOR MALFUNCTION B AND Eº.
If there is no problem on ªPROCEDURE FOR MALFUNCTION
B AND Eº, perform ªPROCEDURE FOR MALFUNCTION Cº.
If there is no problem on ªPROCEDURE FOR MALFUNCTION
Cº, perform ªPROCEDURE FOR MALFUNCTION Dº.
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.
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DTC P0100 MASS AIR FLOW SENSOR (MAFS)
On Board Diagnosis Logic
EC-151