02 sensor INFINITI QX4 2001 Factory Service Manual

Incident Simulation TestsNBGI0004S02INTRODUCTIONNBGI0004S0201Sometimes the symptom is not present when the vehicle is brought
in for service. If possible, re-create the conditions present at the
time of the incident. Doing so may help avoid a No Trouble Found
Diagnosis. The following section illustrates ways to simulate the
conditions/environment under which the owner experiences an
electrical incident.
The section is broken into the six following topics:
IVehicle vibration
IHeat sensitive
IFreezing
IWater intrusion
IElectrical load
ICold or hot start up
Get a thorough description of the incident from the customer. It is
important for simulating the conditions of the problem.
VEHICLE VIBRATIONNBGI0004S0202The problem may occur or become worse while driving on a rough
road or when engine is vibrating (idle with A/C on). In such a case,
you will want to check for a vibration related condition. Refer to the
illustration below.
Connectors & Harness
Determine which connectors and wiring harness would affect the
electrical system you are inspecting.Gentlyshake each connec-
tor and harness while monitoring the system for the incident you
are trying to duplicate. This test may indicate a loose or poor elec-
trical connection.
Hint
Connectors can be exposed to moisture. It is possible to get a thin
film of corrosion on the connector terminals. A visual inspection
may not reveal this without disconnecting the connector. If the
problem occurs intermittently, perhaps the problem is caused by
corrosion. It is a good idea to disconnect, inspect and clean the
terminals on related connectors in the system.
Sensors & Relays
Gentlyapply a slight vibration to sensors and relays in the system
you are inspecting.
This test may indicate a loose or poorly mounted sensor or relay.
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HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Incident Simulation Tests
GI-25

NBGI0010
SAE J1930 Terminology ListNBGI0010S01All emission related terms used in this publication in accordance with SAE J1930 are listed. Accordingly, new
terms, new acronyms/abbreviations and old terms are listed in the following chart.
NEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
Air cleaner ACL Air cleaner
Barometric pressure BARO ***
Barometric pressure sensor-BCDD BAROS-BCDD BCDD
Camshaft position CMP ***
Camshaft position sensor CMPS Crank angle sensor
Canister *** Canister
Carburetor CARB Carburetor
Charge air cooler CAC Intercooler
Closed loop CL Closed loop
Closed throttle position switch CTP switch Idle switch
Clutch pedal position switch CPP switch Clutch switch
Continuous fuel injection system CFI system ***
Continuous trap oxidizer system CTOX system ***
Crankshaft position CKP ***
Crankshaft position sensor CKPS ***
Data link connector DLC ***
Diagnostic test mode DTM Diagnostic mode
Diagnostic test mode selector DTM selector Diagnostic mode selector
Diagnostic test mode I DTM I Mode I
Diagnostic test mode II DTM II Mode II
Diagnostic trouble code DTC Malfunction code
Direct fuel injection system DFI system ***
Distributor ignition system DI system Ignition timing control
Early fuel evaporation-mixture heater EFE-mixture heater Mixture heater
Early fuel evaporation system EFE system Mixture heater control
Electrically erasable programmable read
only memoryEEPROM ***
Electronic ignition system EI system Ignition timing control
Engine control EC ***
Engine control module ECM ECCS control unit
Engine coolant temperature ECT Engine temperature
Engine coolant temperature sensor ECTS Engine temperature sensor
Engine modification EM ***
Engine speed RPM Engine speed
Erasable programmable read only
memoryEPROM ***MA
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SAE J1930 TERMINOLOGY LIST
SAE J1930 Terminology List
GI-51

NEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
Evaporative emission canister EVAP canister Canister
Evaporative emission system EVAP system Canister control solenoid valve
Exhaust gas recirculation valve EGR valve EGR valve
Exhaust gas recirculation control-BPT
valveEGRC-BPT valve BPT valve
Exhaust gas recirculation control-solenoid
valveEGRC-solenoid valve EGR control solenoid valve
Exhaust gas recirculation temperature
sensorEGRT sensor Exhaust gas temperature sensor
EGR temperature sensor
Flash electrically erasable programmable
read only memoryFEEPROM ***
Flash erasable programmable read only
memoryFEPROM ***
Flexible fuel sensor FFS ***
Flexible fuel system FF system ***
Fuel pressure regulator *** Pressure regulator
Fuel pressure regulator control solenoid
valve*** PRVR control solenoid valve
Fuel tank temperature sensor FTT sensor Tank fuel temperature sensor
Fuel trim FT ***
Heated Oxygen sensor HO2S Exhaust gas sensor
Idle air control system IAC system Idle speed control
Idle air control valve-air regulator IACV-air regulator Air regulator
Idle air control valve-auxiliary air control
valveIACV-AAC valve Auxiliary air control (AAC) valve
Idle air control valve-FICD solenoid valve IACV-FICD solenoid valve FICD solenoid valve
Idle air control valve-idle up control sole-
noid valveIACV-idle up control solenoid valve Idle up control solenoid valve
Idle speed control-FI pot ISC-FI pot FI pot
Idle speed control system ISC system ***
Ignition control IC ***
Ignition control module ICM ***
Indirect fuel injection system IFI system ***
Intake air IA Air
Intake air temperature sensor IAT sensor Air temperature sensor
Knock *** Detonation
Knock sensor KS Detonation sensor
Malfunction indicator lamp MIL Check engine light
Manifold absolute pressure MAP ***
Manifold absolute pressure sensor MAPS ***
SAE J1930 TERMINOLOGY LIST
SAE J1930 Terminology List (Cont'd)
GI-52

NEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
Manifold differential pressure MDP ***
Manifold differential pressure sensor MDPS ***
Manifold surface temperature MST ***
Manifold surface temperature sensor MSTS ***
Manifold vacuum zone MVZ ***
Manifold vacuum zone sensor MVZS ***
Mass air flow sensor MAFS Air flow meter
Mixture control solenoid valve MC solenoid valve Air-fuel ratio control solenoid valve
Multiport fuel injection System MFI system Fuel injection control
Neutral position switch *** Neutral switch
Nonvolatile random access memory NVRAM ***
On board diagnostic system OBD system Self-diagnosis
Open loop OL Open loop
Oxidation catalyst OC Catalyst
Oxidation catalytic converter system OC system ***
Oxygen sensor O2S Exhaust gas sensor
Park position switch *** Park switch
Park/neutral position switch PNP switch Park/neutral switch
Periodic trap oxidizer system PTOX system ***
Positive crankcase ventilation PCV Positive crankcase ventilation
Positive crankcase ventilation valve PCV valve PCV valve
Powertrain control module PCM ***
Programmable read only memory PROM ***
Pulsed secondary air injection control
solenoid valvePAIRC solenoid valve AIV control solenoid valve
Pulsed secondary air injection system PAIR system Air induction valve (AIV) control
Pulsed secondary air injection valve PAIR valve Air induction valve
Random access memory RAM ***
Read only memory ROM ***
Scan tool ST ***
Secondary air injection pump AIR pump ***
Secondary air injection system AIR system ***
Sequential multiport fuel injection system SFI system Sequential fuel injection
Service reminder indicator SRI ***
Simultaneous multiport fuel injection sys-
tem*** Simultaneous fuel injection
Smoke puff limiter system SPL system ***
Supercharger SC ***
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SAE J1930 TERMINOLOGY LIST
SAE J1930 Terminology List (Cont'd)
GI-53

NEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
Supercharger bypass SCB ***
System readiness test SRT ***
Thermal vacuum valve TVV Thermal vacuum valve
Three way catalyst TWC Catalyst
Three way catalytic converter system TWC system ***
Three way + oxidation catalyst TWC + OC Catalyst
Three way + oxidation catalytic converter
systemTWC + OC system ***
Throttle body TB Throttle chamber
SPI body
Throttle body fuel injection system TBI system Fuel injection control
Throttle position TP Throttle position
Throttle position sensor TPS Throttle sensor
Throttle position switch TP switch Throttle switch
Torque converter clutch solenoid valve TCC solenoid valve Lock-up cancel solenoid
Lock-up solenoid
Transmission control module TCM A/T control unit
Turbocharger TC Turbocharger
Vehicle speed sensor VSS Vehicle speed sensor
Volume air flow sensor VAFS Air flow meter
Warm up oxidation catalyst WU-OC Catalyst
Warm up oxidation catalytic converter sys-
temWU-OC system ***
Warm up three way catalyst WU-TWC Catalyst
Warm up three way catalytic converter
systemWU-TWC system ***
Wide open throttle position switch WOTP switch Full switch
SAE J1930 TERMINOLOGY LIST
SAE J1930 Terminology List (Cont'd)
GI-54

HEATER &
AIR CONDITIONER
SECTION
HA
CONTENTS
PRECAUTIONS...............................................................2
Supplemental Restraint System (SRS)²AIR
BAG²and²SEAT BELT PRE-TENSIONER²...............2
Precautions for Working with HFC-134a (R-134a) .....2
General Refrigerant Precautions .................................3
Precautions for Leak Detection Dye............................3
Identification .................................................................4
Precautions for Refrigerant Connection ......................4
Precautions for Servicing Compressor ........................6
Precautions for Service Equipment .............................7
Wiring Diagrams and Trouble Diagnoses....................9
PREPARATION.............................................................10
Special Service Tools ................................................10
HFC-134a (R-134a) Service Tools and
Equipment .................................................................. 11
DESCRIPTION...............................................................14
Refrigeration System .................................................14
V-6 Variable Displacement Compressor....................15
Component Layout ....................................................19
Introduction ................................................................20
Features .....................................................................20
Overview of Control System ......................................23
Control Operation ......................................................23
Discharge Air Flow.....................................................25
System Description ....................................................26
TROUBLE DIAGNOSES................................................27
Component Location..................................................27
Circuit Diagram (Without Navigation System) ...........30
Wiring Diagram - A/C, A - (Without Navigation
System) ......................................................................31
Circuit Diagram (With Navigation System) ................35
Wiring Diagram - A/C, A - (With Navigation
System) ......................................................................36
Auto Amp. Terminals and Reference Value...............40
Self-diagnosis ............................................................44
How to Perform Trouble Diagnoses for Quick
and Accurate Repair ..................................................65Operational Check .....................................................66
A/C System ................................................................71
Mode Door Motor.......................................................75
Air Mix Door Motor ....................................................82
Intake Door Motor ......................................................87
Blower Motor..............................................................95
Magnet Clutch..........................................................104
Insufficient Cooling .................................................. 112
Insufficient Heating ..................................................121
Noise ........................................................................123
Self-diagnosis ..........................................................124
Memory Function .....................................................126
ECON (ECONOMY) Mode ......................................128
Ambient Sensor Circuit ............................................129
In-vehicle Sensor Circuit..........................................132
Sunload Sensor Circuit ............................................135
Intake Sensor Circuit ...............................................139
Air Mix Door Motor PBR Circuit ..............................141
Multiplex Communication Circuit .............................142
SERVICE PROCEDURE..............................................144
HFC-134a (R-134a) Service Procedure ..................144
Maintenance of Lubricant Quantity in
Compressor .............................................................146
Compressor .............................................................149
Compressor Clutch ..................................................150
Refrigerant Lines .....................................................154
Belt ...........................................................................159
Ventilation Air Filter ..................................................159
SERVICE DATA AND SPECIFICATIONS (SDS).......160
Compressor .............................................................160
Lubricant ..................................................................160
Refrigerant ...............................................................160
Engine Idling Speed (When A/C is ON) ..................160
Belt Tension .............................................................160
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Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBHA0001The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), seat belt
pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of front side air bag module (located in the outer side of front
seat), satellite sensor, diagnosis sensor unit (one of components of air bags for a frontal collision), wiring
harness, warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
ITo avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be performed
by an authorized INFINITI dealer.
IImproper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the RS section.
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
Precautions for Working with HFC-134a
(R-134a)
NBHA0002WARNING:
ICFC-12 (R-12) refrigerant and HFC-134a (R-134a) refrigerant are not compatible. If the refrigerants
are mixed and compressor failure is likely to occur, refer to ªCONTAMINATED REFRIGERANTº
below. To determine the purity of HFC-134a (R-134a) in the vehicle and recovery tank, use Refrig-
erant Recovery/Recycling Recharging equipment (ACR4) (J-39500-INF) and Refrigerant Identifier.
IUse only specified lubricant for the HFC-134a (R-134a) A/C system and HFC-134a (R-134a) compo-
nents. If lubricant other than that specified is used, compressor failure is likely to occur.
IThe specified HFC-134a (R-134a) lubricant rapidly absorbs moisture from the atmosphere. The fol-
lowing handling precautions must be observed:
a) When removing refrigerant components from a vehicle, immediately cap (seal) the component to
minimize the entry of moisture from the atmosphere.
b) When installing refrigerant components to a vehicle, do not remove the caps (unseal) until just
before connecting the components. Connect all refrigerant loop components as quickly as pos-
sible to minimize the entry of moisture into system.
c) Only use the specified lubricant from a sealed container. Immediately reseal containers of lubri-
cant. Without proper sealing, lubricant will become moisture saturated and should not be used.
d) Avoid breathing A/C refrigerant and lubricant vapor or mist. Exposure may irritate eyes, nose and
throat. Remove R-134a from the A/C system, using certified service equipment meeting require-
ments of SAE J2210 (R-134a recycling equipment), or J2209 (R-134a recovery equipment). If acci-
dental system discharge occurs, ventilate work area before resuming service. Additional health and
safety information may be obtained from refrigerant and lubricant manufacturers.
e) Do not allow lubricant (Nissan A/C System Oil Type S) to come in contact with styrofoam parts.
Damage may result.
CONTAMINATED REFRIGERANTNBHA0002S01If a refrigerant other than pure R-134a is identified in a vehicle, your options are:
IExplain to the customer that environmental regulations prohibit the release of contaminated refrigerant into
the atmosphere.
IExplain that recovery of the contaminated refrigerant could damage your service equipment and refriger-
ant supply.
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
HA-2

Refrigeration System
REFRIGERATION CYCLENBHA0010Refrigerant FlowNBHA0010S01The refrigerant flows in the standard pattern, that is, through the compressor, the condenser, the liquid tank,
through the evaporator, and back to the compressor. The refrigerant evaporation through the evaporator coil
is controlled by an externally equalized expansion valve, located inside the evaporator case.
Freeze ProtectionNBHA0010S02Under normal operating conditions, when the A/C is switched on, the compressor runs continuously, and the
evaporator pressure, and therefore temperature, is controlled by the V-6 variable displacement compressor to
prevent freeze up.
Refrigerant System ProtectionNBHA0010S03Refrigerant Pressure SensorNBHA0010S0303The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure
sensor, located on the liquid tank. If the system pressure rises above, or falls below the specifications, the
refrigerant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the
ECM. ECM makes the A/C relay go OFF and stops the compressor when pressure on the high pressure side
detected by refrigerant pressure sensor is over about 2,746 kPa (28 kg/cm
2, 398 psi) or below about 177 kPa
(1.8 kg/cm2, 26 psi).
Pressure Relief Valve
NBHA0010S0302The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compres-
sor. When the pressure of refrigerant in the system increases to an abnormal level [more than 3,727 kPa (38
kg/cm
2, 540 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant
into the atmosphere.
RHA347H
DESCRIPTION
Refrigeration System
HA-14

IntroductionNBHA0013AIR CONDITIONER LAN SYSTEM OVERVIEW CONTROL SYSTEMNBHA0013S01The LAN system consists of auto amp., air mix door motor and mode door motor.
A configuration of these components is shown in the diagram below.
RHA439G
FeaturesNBHA0014SYSTEM CONSTRUCTION (LAN)NBHA0014S08A small network is constructed between the auto amplifier, air mix door motor and mode door motor. The auto
amplifier and motors are connected by data transmission lines and motor power supply lines. The LAN net-
work is built through the ground circuits of the two motors.
Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted
through the data transmission lines connecting the auto amplifier and two motors.
The following functions are contained in LCUs built into the air mix door motor and the mode door motor.
IAddress
IMotor opening angle signals
IData transmission
IMotor stop and drive decision
IOpening angle sensor (PBR function)
IComparison
IDecision (Auto amplifier indicated value and motor opening angle comparison)
RHA440GA
OperationNBHA0014S0801The auto amplifier receives data from each of the sensors. The amplifier sends air mix door and mode door
opening angle data to the air mix door motor LCU and mode door motor LCU.
The air mix door motor and mode door motor read their respective signals according to the address signal.
Opening angle indication signals received from the auto amplifier and each of the motor position sensors are
compared by the LCUs in each motor with the existing decision and opening angles. Subsequently, HOT/
COLD or DEFROST/VENT operation is selected. The new selection data is returned to the auto amplifier.
DESCRIPTION
Introduction
HA-20

Fan Speed ControlNBHA0014S0804Blower speed is automatically controlled based on temperature setting, ambient temperature, in-vehicle
temperature, intake temperature, amount of sunload and air mix door position.
With FAN switch set to ªAUTOº, the blower motor starts to gradually increase air flow volume.
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flow-
ing.
Intake Door ControlNBHA0014S0805The intake doors are automatically controlled by: The temperature setting, ambient temperature, in-vehicle
temperature, intake temperature, amount of sunload and ON-OFF operation of the compressor.
Outlet Door ControlNBHA0014S0806The outlet door is automatically controlled by: The temperature setting, ambient temperature, in-vehicle
temperature, intake temperature and amount of sunload.
Magnet Clutch ControlNBHA0014S0807The ECM controls compressor operation using input signals from the throttle position sensor and auto ampli-
fier.
Self-diagnostic SystemNBHA0014S0808The self-diagnostic system is built into the auto amplifier (LCU) to quickly locate the cause of problems.
DESCRIPTION
Features (Cont'd)
HA-22