2001 INFINITI QX4 Oil sensor

CONSULT-II Reference Value in Data Monitor
Mode ........................................................................585
ECM Terminals and Reference Value .....................585
On Board Diagnosis Logic.......................................586
Possible Cause ........................................................586
DTC Confirmation Procedure ..................................586
Wiring Diagram ........................................................587
Diagnostic Procedure ..............................................588
DTC P1491 VACUUM CUT VALVE BYPASS
VALVE..........................................................................591
Description ...............................................................591
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................591
ECM Terminals and Reference Value .....................591
On Board Diagnosis Logic.......................................592
Possible Cause ........................................................592
DTC Confirmation Procedure ..................................592
Overall Function Check ...........................................593
Wiring Diagram ........................................................594
Diagnostic Procedure ..............................................595
DTC P1605 A/T DIAGNOSIS COMMUNICATION
LINE.............................................................................603
Component Description ...........................................603
On Board Diagnosis Logic.......................................603
Possible Cause ........................................................603
DTC Confirmation Procedure ..................................603
DTC P1706 PARK/NEUTRAL POSITION (PNP)
SWITCH.......................................................................604
Component Description ...........................................604
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................604
ECM Terminals and Reference Value .....................604
On Board Diagnosis Logic.......................................604
Possible Cause ........................................................604
DTC Confirmation Procedure ..................................605
Overall Function Check ...........................................606
Wiring Diagram ........................................................607
Diagnostic Procedure ..............................................608
VARIABLE INDUCTION AIR CONTROL SYSTEM
(VIAS)...........................................................................610
Description ...............................................................610
ECM Terminals and Reference Value ..................... 611
Wiring Diagram ........................................................612
Diagnostic Procedure ..............................................613
INJECTOR...................................................................616
Component Description ...........................................616
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................616
ECM Terminals and Reference Value .....................616
Wiring Diagram ........................................................617Diagnostic Procedure ..............................................618
START SIGNAL...........................................................621
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................621
ECM Terminals and Reference Value .....................621
Wiring Diagram ........................................................622
Diagnostic Procedure ..............................................623
FUEL PUMP.................................................................625
System Description ..................................................625
Component Description ...........................................625
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................625
ECM Terminals and Reference Value .....................626
Wiring Diagram ........................................................627
Diagnostic Procedure ..............................................628
POWER STEERING OIL PRESSURE SWITCH.........634
Component Description ...........................................634
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................634
ECM Terminals and Reference Value .....................634
Wiring Diagram ........................................................635
Diagnostic Procedure ..............................................636
REFRIGERANT PRESSURE SENSOR......................639
Description ...............................................................639
ECM Terminals and Reference Value .....................639
Wiring Diagram ........................................................640
Diagnostic Procedure ..............................................641
ELECTRICAL LOAD SIGNAL.....................................643
ECM Terminals and Reference Value .....................643
Wiring Diagram ........................................................644
Diagnostic Procedure ..............................................645
MIL & DATA LINK CONNECTORS............................648
Wiring Diagram ........................................................648
SERVICE DATA AND SPECIFICATIONS (SDS).......649
Fuel Pressure Regulator..........................................649
Idle Speed and Ignition Timing ................................649
Mass Air Flow Sensor..............................................649
Engine Coolant Temperature Sensor ......................649
Heated Oxygen Sensor 1 Heater (Front) ................649
Fuel Pump ...............................................................649
IACV-AAC Valve ......................................................649
Injector .....................................................................649
Resistor ....................................................................649
Throttle Position Sensor ..........................................650
Calculated Load Value.............................................650
Intake Air Temperature Sensor ................................650
Heated Oxygen Sensor 2 Heater (Rear).................650
Crankshaft Position Sensor (REF) ..........................650
Fuel Tank Temperature Sensor ...............................650
Camshaft Position Sensor (PHASE) .......................650GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
CONTENTS(Cont'd)
EC-7

System ChartNBEC0013
Input (Sensor) ECM Function Output (Actuator)
ICamshaft position sensor (PHASE)
ICrankshaft position sensor (REF)
IMass air flow sensor
IEngine coolant temperature sensor
IHeated oxygen sensor 1 (front)
IIgnition switch
IThrottle position sensor
IClosed throttle position switch*3
IPark/neutral position (PNP) switch
IAir conditioner switch
IKnock sensor
IIntake air temperature sensor
IAbsolute pressure sensor
IEVAP control system pressure sensor*1
IBattery voltage
IPower steering oil pressure switch
IVehicle speed sensor
IFuel tank temperature sensor*1
ICrankshaft position sensor (POS)
IHeated oxygen sensor 2 (rear)*2
ITCM (Transmission control module)
IRefrigerant pressure sensor
IElectrical load
IFuel level sensor*1Fuel injection & mixture ratio control Injectors
Electronic ignition system Power transistor
Idle air control system IACV-AAC valve
Fuel pump control Fuel pump relay
On board diagnostic system MIL (On the instrument panel)
Swirl control valve controlSwirl control valve control solenoid
valve
Power valve control VIAS control solenoid valve
Heated oxygen sensor 1 heater (front) con-
trolHeated oxygen sensor 1 heater
(front)
Heated oxygen sensor 2 heater (rear) controlHeated oxygen sensor 2 heater
(rear)
EVAP canister purge flow controlEVAP canister purge volume con-
trol solenoid valve
Air conditioning cut control Air conditioner relay
ON BOARD DIAGNOSIS for EVAP systemIEVAP canister vent control valve
IVacuum cut valve bypass valve
*1: These sensors are not used to control the engine system. They are used only for the on board diagnosis.
*2: This sensor is not used to control the engine system under normal conditions.
*3: This switch will operate in place of the throttle position sensor to control EVAP parts if the sensor malfunctions.GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE AND EMISSION CONTROL OVERALL SYSTEM
System Chart
EC-27

Multiport Fuel Injection (MFI) System
DESCRIPTIONNBEC0014Input/Output Signal ChartNBEC0014S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed (POS signal)
Fuel injec-
tion & mix-
ture ratio
controlInjectors Crankshaft position sensor (REF) Engine speed (REF signal)
Camshaft position sensor (PHASE) Piston position
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Heated oxygen sensor 1 (front) Density of oxygen in exhaust gas
Throttle position sensorThrottle position
Throttle valve idle position
Park/neutral position (PNP) switch Gear position
Vehicle speed sensor Vehicle speed
Ignition switch Start signal
Air conditioner switch Air conditioner operation
Knock sensor Engine knocking condition
Battery Battery voltage
Absolute pressure sensor Ambient air barometric pressure
Power steering oil pressure switch Power steering operation
Heated oxygen sensor 2 (rear)* Density of oxygen in exhaust gas
*: Under normal conditions, this sensor is not for engine control operation.
Basic Multiport Fuel Injection SystemNBEC0014S02The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the crankshaft position sensor and the mass air
flow sensor.
Various Fuel Injection Increase/Decrease CompensationNBEC0014S03In addition, the amount of fuel injected is compensated to improve engine performance under various oper-
ating conditions as listed below.

IDuring warm-up
IWhen starting the engine
IDuring acceleration
IHot-engine operation
IWhen selector lever is changed from ªNº to ªDº
IHigh-load, high-speed operation

IDuring deceleration
IDuring high engine speed operation
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Multiport Fuel Injection (MFI) System
EC-28

System DescriptionNBEC0015S02
SEF742M
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of
the engine. The ignition timing data is stored in the ECM. This data forms the map shown.
The ECM receives information such as the injection pulse width and camshaft position sensor signal. Com-
puting this information, ignition signals are transmitted to the power transistor.
e.g., N: 1,800 rpm, Tp: 1.50 msec
A ÉBTDC
During the following conditions, the ignition timing is revised by the ECM according to the other data stored
in the ECM.
IAt starting
IDuring warm-up
IAt idle
IAt low battery voltage
IDuring acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
Air Conditioning Cut Control
DESCRIPTIONNBEC0016Input/Output Signal ChartNBEC0016S01
Sensor Input Signal to ECM ECM function Actuator
Air conditioner switch Air conditioner ªONº signal
Air conditioner
cut controlAir conditioner relay Throttle position sensor Throttle valve opening angle
Crankshaft position sensor (POS) Engine speed (POS signal)
Crankshaft position sensor (REF) Engine speed (REF signal)
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Vehicle speed sensor Vehicle speed
Refrigerant pressure sensor Refrigerant pressure
Power steering oil pressure switch Power steering operation
System DescriptionNBEC0016S02This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.
IWhen the accelerator pedal is fully depressed.
IWhen cranking the engine.
IAt high engine speeds.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Electronic Ignition (EI) System (Cont'd)
EC-31

ENGINE CONTROL COMPONENT PARTS/CONTROL
SYSTEMS APPLICATION
NBEC0034S02
ItemDIAGNOSTIC TEST MODE
WORK
SUP-
PORTSELF-DIAGNOSTIC
RESULTS
D ATA
MONI-
TORD ATA
MONI-
TOR
(SPEC)ACTIVE
TESTDTC & SRT
CONFIRMATION
DTC*1FREEZE
FRAME
DATA*2SRT
STATUSDTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor
(POS)XXXX
Crankshaft position sensor (REF) X X X
Mass air flow sensor X X X
Engine coolant temperature sen-
sorXXXXX
Heated oxygen sensor 1 (front) X X X X X
Heated oxygen sensor 2 (rear) X X X X X
Vehicle speed sensorXXXX
Throttle position sensor X X X
Fuel tank temperature sensor X X X X
EVAP control system pressure
sensorXXX
Absolute pressure sensor X X X
Intake air temperature sensor X X X
Knock sensor X
Ignition switch (start signal) X X
Closed throttle position switch X X X
Closed throttle position switch
(throttle position sensor signal)XX
Air conditioner switch X X
Park/neutral position (PNP)
switchXXX
Power steering oil pressure
switchXX
Battery voltage X X
Ambient air temperature switch X X
Load signal X X
Swirl control valve control
vacuum check switchXXX
Fuel level sensor X X X
Intake valve timing control posi-
tion sensorXXX
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-82

Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
INT/A TEMP SE
[ÉC] or [ÉF]qqIThe intake air temperature determined
by the signal voltage of the intake air
temperature sensor is indicated.
EVAP SYS PRES [V]qIThe signal voltage of EVAP control sys-
tem pressure sensor is displayed.
ABSOL PRES/SE [V]qIThe signal voltage of the absolute pres-
sure sensor is displayed.
FUEL LEVEL SE [V]qIThe signal voltage of the fuel level sen-
sor is displayed.
START SIGNAL
[ON/OFF]qqIIndicates [ON/OFF] condition from the
starter signal.IAfter starting the engine, [OFF] is dis-
played regardless of the starter signal.
CLSD THL POS
[ON/OFF]qqIIndicates idle position [ON/OFF] com-
puted by ECM according to the throttle
position sensor signal.
CLSD THL/P SW
[ON/OFF]qIIndicates mechanical contact [ON/OFF]
condition of the closed throttle position
switch.
AIR COND SIG
[ON/OFF]qqIIndicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
P/N POSI SW
[ON/OFF]qqIIndicates [ON/OFF] condition from the
park/neutral position (PNP) switch sig-
nal.
PW/ST SIGNAL
[ON/OFF]qqI[ON/OFF] condition of the power steer-
ing oil pressure switch determined by
the power steering oil pressure signal is
indicated.
LOAD SIGNAL
[ON/OFF]qqIIndicates [ON/OFF] condition from the
electrical load signal and/or lighting
switch.
ON ... rear defogger is operating and/or
lighting switch is on.
OFF ... rear defogger is not operating
and lighting switch is not on.
IGNITION SW
[ON/OFF]qIIndicates [ON/OFF] condition from igni-
tion switch.
SWRL CONT S/V
[ON/OFF]qIThe control condition of the swirl con-
trol valve control solenoid valve (deter-
mined by ECM according to the input
signals) is indicated.
ION ... Swirl control valve is closed.
OFF ... Swirl control valve is opened.
INJ PULSE-B1
[msec]q
IIndicates the actual fuel injection pulse
width compensated by ECM according
to the input signals.IWhen the engine is stopped, a certain
computed value is indicated.
INJ PULSE-B2
[msec]
B/FUEL SCHDL
[msec]qIªBase fuel scheduleº indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board
correction.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-88

Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
A/F ALPHA-B1 [%]q
IIndicates the mean value of the air-fuel ratio
feedback correction factor per cycle.IWhen the engine is running, specifi-
cation range is indicated.
IThis data also includes the data for
the air-fuel ratio learning control. A/F ALPHA-B2 [%]q
NOTE:
IAny monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
IRegarding R50 model, ªB1º indicates bank 1 and ªB2º indicates bank 2.
ACTIVE TEST MODENBEC0034S07
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJECTIONIEngine: Return to the original
trouble condition
IChange the amount of fuel injec-
tion using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IHarness and connector
IFuel injectors
IHeated oxygen sensor
IGNITION TIMINGIEngine: Return to the original
trouble condition
ITiming light: Set
IRetard the ignition timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IAdjust initial ignition timing
IACV-AAC/V
OPENINGIEngine: After warming up, idle
the engine.
IChange the IACV-AAC valve
opening percent using CON-
SULT-II.Engine speed changes according
to the opening percent.IHarness and connector
IIACV-AAC valve
POWER BAL-
ANCEIEngine: After warming up, idle
the engine.
IA/C switch ªOFFº
IShift lever ªNº
ICut off each injector signal one
at a time using CONSULT-II.Engine runs rough or dies.IHarness and connector
ICompression
IInjectors
IPower transistor
ISpark plugs
IIgnition coils
ENG COOLANT
TEMPIEngine: Return to the original
trouble condition
IChange the engine coolant tem-
perature using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IHarness and connector
IEngine coolant temperature sen-
sor
IFuel injectors
FUEL PUMP
RELAYIIgnition switch: ON
(Engine stopped)
ITurn the fuel pump relay ªONº
and ªOFFº using CONSULT-II
and listen to operating sound.Fuel pump relay makes the operat-
ing sound.IHarness and connector
IFuel pump relay
VIAS SOL VALVEIIgnition switch: ON
ITurn solenoid valve ªONº and
ªOFFº with CONSULT-II and lis-
ten for operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
SWIRL CONT
S O L VA LV EIIgnition switch: ON
ITurn solenoid valve ªONº and
ªOFFº with CONSULT-II and lis-
ten for operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
PURG VOL
CONT/VIEngine: After warming up, run
engine at 1,500 rpm.
IChange the EVAP canister purge
volume control solenoid valve
opening percent using CON-
SULT-II.Engine speed changes according
to the opening percent.IHarness and connector
ISolenoid valve
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-91

SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Engine
controlCrankshaft position sensor (REF)
circuit
22EC-510
Crankshaft position sensor (POS)
circuitEC-334, 517
Camshaft position sensor
(PHASE) circuit3EC-342
Mass air flow sensor circuit 1
122
222 2EC-150
Heated oxygen sensor 1 (front)
circuit
3EC-192
Engine coolant temperature sen-
sor circuit1 3 3 EC-169, 187
Throttle position sensor circuit 2 2 EC-174
Incorrect throttle position sensor
adjustment3 1 1 1 1 1 1 1 EC-101
Vehicle speed sensor circuit 2 3 3
3EC-417
Knock sensor circuit 2 EC-328
ECM 2233333 3 33EC-444, 117
Start signal circuit 2 EC-621
Park/Neutral position switch circuit 3 3
333 EC-604
Power steering oil pressure switch
circuit2 EC-634
Electrical load signal circuitEC-644
1 - 6: The numbers refer to the order of inspection.
(continued on next page)
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Matrix Chart (Cont'd)
EC-119