2001 INFINITI QX4 air condition

80845-71L00: 30 mm (1.18 in) thick, 30 x 50 mm (1.18 x 1.97 in)
FELT CLOTH TAPE
Used to insulate where movement does not occur. Ideal for instrument panel applications.
68370-4B000: 15 x 25 mm (0.59 x 0.98 in) pad/68239-13E00: 5 mm (0.20 in) wide tape roll
The following materials, not found in the kit, can also be used to repair squeaks and rattles.
UHMW (TEFLON) TAPE
Insulates where slight movement is present. Ideal for instrument panel applications.
SILICONE GREASE
Used in place of UHMW tape that will be visible or not fit.
Note: Will only last a few months.
SILICONE SPRAY
Use when grease cannot be applied.
DUCT TAPE
Use to eliminate movement.
CONFIRM THE REPAIRNBBT0024S06Confirm that the cause of a noise is repaired by test driving the vehicle. Operate the vehicle under the same
conditions as when the noise originally occurred. Refer to the notes on the Diagnostic Worksheet.
Generic Squeak and Rattle TroubleshootingNBBT0025Refer to Table of Contents for specific component removal and installation information.
INSTRUMENT PANELNBBT0025S01Most incidents are caused by contact and movement between:
1. The cluster lid A and instrument panel
2. Acrylic lens and combination meter housing
3. Instrument panel to front pillar garnish
4. Instrument panel to windshield
5. Instrument panel mounting pins
6. Wiring harnesses behind the combination meter
7. A/C defroster duct and duct joint
These incidents can usually be located by tapping or moving the components to duplicate the noise or by
pressing on the components while driving to stop the noise. Most of these incidents can be repaired by apply-
ing felt cloth tape or silicon spray (in hard to reach areas). Urethane pads can be used to insulate wiring har-
ness.
CAUTION:
Do not use silicone spray to isolate a squeak or rattle. If you saturate the area with silicone, you will
not be able to recheck the repair.
CENTER CONSOLENBBT0025S02Components to pay attention to include:
1. Shifter assembly cover to finisher
2. A/C control unit and cluster lid C
3. Wiring harnesses behind audio and A/C control unit
The instrument panel repair and isolation procedures also apply to the center console.
DOORSNBBT0025S03Pay attention to the:
1. Finisher and inner panel making a slapping noise
2. Inside handle escutcheon to door finisher
3. Wiring harnesses tapping
4. Door striker out of alignment causing a popping noise on starts and stops
Tapping or moving the components or pressing on them while driving to duplicate the conditions can isolate
many of these incidents. You can usually insulate the areas with felt cloth tape or insulator foam blocks from
the Nissan Squeak and Rattle Kit (J-43980) to repair the noise.
SQUEAK AND RATTLE TROUBLE DIAGNOSES
Work Flow (Cont'd)
BT-6

TRUNK=NBBT0025S04Trunk noises are often caused by a loose jack or loose items put into the trunk by the owner.
In addition look for:
1. Trunk lid bumpers out of adjustment
2. Trunk lid striker out of adjustment
3. The trunk lid torsion bars knocking together
4. A loose license plate or bracket
Most of these incidents can be repaired by adjusting, securing or insulating the item(s) or component(s) caus-
ing the noise.
SUNROOF/HEADLINERNBBT0025S05Noises in the sunroof/headliner area can often be traced to one of the following:
1. Sunroof lid, rail, linkage or seals making a rattle or light knocking noise
2. Sunvisor shaft shaking in the holder
3. Front or rear windshield touching headliner and squeaking
Again, pressing on the components to stop the noise while duplicating the conditions can isolate most of these
incidents. Repairs usually consist of insulating with felt cloth tape.
SEATSNBBT0025S06When isolating seat noises it's important to note the position the seat is in and the load placed on the seat
when the noise is present. These conditions should be duplicated when verifying and isolating the cause of
the noise.
Cause of seat noise include:
1. Headrest rods and holders
2. A squeak between the seat pad cushion and frame
3. The rear seat back lock and bracket
These noises can be isolated by moving or pressing on the suspected components while duplicating the con-
ditions under which the noise occurs. Most of these incidents can be repaired by repositioning the component
or applying urethane tape to the contact area.
UNDERHOODNBBT0025S07Some interior noises may be caused by components under the hood or on the engine wall. The noise is then
transmitted into the passenger compartment.
Causes of transmitted underhood noises include:
1. Any component mounted to the engine wall
2. Components that pass through the engine wall
3. Engine wall mounts and connectors
4. Loose radiator mounting pins
5. Hood bumpers out of adjustment
6. Hood striker out of adjustment
These noises can be difficult to isolate since they cannot be reached from the interior of the vehicle. The best
method is to secure, move or insulate one component at a time and test drive the vehicle. Also, engine RPM
or load can be changed to isolate the noise. Repairs can usually be made by moving, adjusting, securing, or
insulating the component causing the noise.
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SQUEAK AND RATTLE TROUBLE DIAGNOSES
Generic Squeak and Rattle Troubleshooting (Cont'd)
BT-7

ENGINE CONTROL SYSTEM
SECTION
EC
CONTENTS
TROUBLE DIAGNOSIS - INDEX....................................8
Alphabetical & P No. Index for DTC ...........................8
PRECAUTIONS.............................................................14
Supplemental Restraint System (SRS)²AIR
BAG²and²SEAT BELT PRE-TENSIONER².............14
Precautions for On Board Diagnostic (OBD)
System of Engine and A/T.........................................14
Engine Fuel & Emission Control System ..................15
Precautions ................................................................16
Wiring Diagrams and Trouble Diagnosis ...................17
PREPARATION.............................................................18
Special Service Tools ................................................18
Commercial Service Tools .........................................18
ENGINE AND EMISSION CONTROL OVERALL
SYSTEM.........................................................................20
Engine Control Component Parts Location ...............20
Circuit Diagram ..........................................................24
System Diagram ........................................................25
Vacuum Hose Drawing ..............................................26
System Chart .............................................................27
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTION...............................................28
Multiport Fuel Injection (MFI) System .......................28
Electronic Ignition (EI) System ..................................30
Air Conditioning Cut Control ......................................31
Fuel Cut Control (at no load & high engine
speed) ........................................................................32
Evaporative Emission System ...................................32
Positive Crankcase Ventilation ..................................38
BASIC SERVICE PROCEDURE...................................39
Fuel Pressure Release ..............................................39
Fuel Pressure Check .................................................39
Fuel Pressure Regulator Check ................................40
Injector .......................................................................41
How to Check Idle Speed and Ignition Timing ..........42
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment .................................................................43
Idle Air Volume Learning ...........................................57ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION...............................................................59
Introduction ................................................................59
Two Trip Detection Logic ...........................................59
Emission-related Diagnostic Information ...................60
Malfunction Indicator Lamp (MIL) ..............................74
OBD System Operation Chart ...................................75
CONSULT-II ...............................................................81
Generic Scan Tool (GST) ..........................................95
TROUBLE DIAGNOSIS - INTRODUCTION..................97
Introduction ................................................................97
Work Flow ..................................................................99
TROUBLE DIAGNOSIS - BASIC INSPECTION.........101
Basic Inspection.......................................................101
TROUBLE DIAGNOSIS - GENERAL
DESCRIPTION............................................................. 116
DTC Inspection Priority Chart.................................. 116
Fail-safe Chart ......................................................... 117
Symptom Matrix Chart ............................................. 118
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................122
Major Sensor Reference Graph in Data Monitor
Mode ........................................................................124
ECM Terminals and Reference Value .....................127
TROUBLE DIAGNOSIS - SPECIFICATION VALUE..136
Description ...............................................................136
Testing Condition .....................................................136
Inspection Procedure ...............................................136
Diagnostic Procedure ..............................................137
TROUBLE DIAGNOSIS FOR INTERMITTENT
INCIDENT.....................................................................140
Description ...............................................................140
Diagnostic Procedure ..............................................140
TROUBLE DIAGNOSIS FOR POWER SUPPLY........141
ECM Terminals and Reference Value .....................141
Main Power Supply and Ground Circuit ..................142
DTC P0100 MASS AIR FLOW SENSOR (MAFS)......150
Component Description ...........................................150
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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
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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

Mixture Ratio Feedback Control (Closed loop control)NBEC0014S04
SEF336WA
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission con-
trol. The warm-up three way catalyst can then better reduce CO, HC and NOx emissions. This system uses
a heated oxygen sensor 1 (front) in the exhaust manifold to monitor if the engine operation is rich or lean. The
ECM adjusts the injection pulse width according to the sensor voltage signal. For more information about the
heated oxygen sensor 1 (front), refer to EC-192. This maintains the mixture ratio within the range of stoichio-
metric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 (rear) is located downstream of the warm-up three way catalyst. Even if the switch-
ing characteristics of the heated oxygen sensor 1 (front) shift, the air-fuel ratio is controlled to stoichiometric
by the signal from the heated oxygen sensor 2 (rear).
Open Loop ControlNBEC0014S05The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
IDeceleration and acceleration
IHigh-load, high-speed operation
IMalfunction of heated oxygen sensor 1 (front) or its circuit
IInsufficient activation of heated oxygen sensor 1 (front) at low engine coolant temperature
IHigh engine coolant temperature
IDuring warm-up
IAfter shifting from ªNº to ªDº
IWhen starting the engine
Mixture Ratio Self-learning ControlNBEC0014S06The mixture ratio feedback control system monitors the mixture ratio signal transmitted from the heated oxy-
gen sensor 1 (front). This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio
as close to the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily con-
trolled as originally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and char-
acteristic changes during operation (i.e., injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This
is then computed in terms of ªinjection pulse durationº to automatically compensate for the difference between
the two ratios.
ªFuel trimº refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
ªShort term fuel trimº is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from the heated oxygen sensor 1 (front) indicates whether the mixture ratio is RICH or LEAN
compared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is
rich, and an increase in fuel volume if it is lean.
ªLong term fuel trimº is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
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ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Multiport Fuel Injection (MFI) System (Cont'd)
EC-29

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.
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ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Electronic Ignition (EI) System (Cont'd)
EC-31

IWhen the engine coolant temperature becomes excessively high.
IWhen operating power steering during low engine speed or low vehicle speed.
IWhen engine speed is excessively low.
IWhen refrigerant pressure is excessively low or high.
Fuel Cut Control (at no load & high engine
speed)
DESCRIPTIONNBEC0017Input/Output Signal ChartNBEC0017S01
Sensor Input Signal to ECMECM func-
tionActuator
Vehicle speed sensor Vehicle speed
Fuel cut
controlInjectors Park/neutral position (PNP) switch Neutral position
Throttle position sensor Throttle position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS) Engine speed (POS signal)
Crankshaft position sensor (REF) Engine speed (REF signal)
If the engine speed is above 1,800 rpm with no load (for example, in neutral and engine speed over 1,800
rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies based on engine speed.
Fuel cut will operate until the engine speed reaches 1,500 rpm, then fuel cut is cancelled.
NOTE:
This function is different from deceleration control listed under ªMultiport Fuel Injection (MFI) Systemº, EC-28.
Evaporative Emission System
DESCRIPTIONNBEC0018
SEF927U
The evaporative emission system is used to reduce hydrocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplished by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into the EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not operating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume control solenoid valve is controlled by ECM. When the engine
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Air Conditioning Cut Control (Cont'd)
EC-32