sensor NISSAN X-TRAIL 2003 Service Repair Manual

EC-486
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PRECAUTIONS

PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EBS010WG
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. Information necessary to service the system safely is included in the SRS and SB section of
this Service Manual.
WARNING:

To 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 per-
formed by an authorized NISSAN/INFINITI dealer.

Improper 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 SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
On Board Diagnostic (OBD) System of EngineEBS010WH
The ECM has an on board diagnostic system. It will light up the malfunction indicator (MI) to warn the driver of
a malfunction causing emission deterioration.
CAUTION:

Be sure to turn the ignition switch OFF and disconnect the battery ground cable before any repair
or inspection work. The open/short circuit of related switches, sensors, solenoid valves, etc. will
cause the MI to light up.

Be sure to connect and lock the connectors securely after work. A loose (unlocked) connector will
cause the MI to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)

Certain systems and components, especially those related to OBD, may use a new style slide-
locking type harness connector. For description and how to disconnect, refer to PG-70, "
HAR-
NESS CONNECTOR" .

Be sure to route and secure the harnesses properly after work. The interference of the harness
with a bracket, etc. may cause the MI to light up due to the short circuit.

Be sure to erase the unnecessary malfunction information (repairs completed) from the ECM.
PrecautionEBS010WI

Always use a 12 volt battery as power source.

Do not attempt to disconnect battery cables while engine is
running.

Before connecting or disconnecting the ECM harness con-
nector, turn ignition switch OFF and disconnect battery
ground cable. Failure to do so may damage the ECM
because battery voltage is applied to ECM even if ignition
switch is turned OFF.

Before removing parts, turn ignition switch OFF and then
disconnect battery ground cable.
SEF289H

PRECAUTIONS
EC-487
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Do not disassemble ECM.

If battery cable is disconnected, the memory will return to
the initial ECM values.
The ECM will now start to self-control at its initial values.
Engine operation can vary slightly when the cable is dis-
connected. However, this is not an indication of a malfunc-
tion. Do not replace parts because of a slight variation.

When connecting ECM harness connector, fasten it
securely with levers as far as they will go as shown in the
figure.

When connecting or disconnecting pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM
pin terminal, when connecting pin connectors.

Securely connect ECM harness connectors.
A poor connection can cause an extremely high (surge)
voltage to develop in coil and condenser, thus resulting in
damage to ICs.

Keep engine control system harness at least 10 cm (4 in)
away from adjacent harness, to prevent engine control sys-
tem malfunctions due to receiving external noise, degraded
operation of ICs, etc.

Keep engine control system parts and harness dry.

Before replacing ECM, perform ECM Terminals and Refer-
ence Value inspection and make sure ECM functions prop-
erly. Refer to EC-543
.

Handle mass air flow sensor carefully to avoid damage.

Do not disassemble mass air flow sensor.

Do not clean mass air flow sensor with any type of deter-
gent.

Do not disassemble electric throttle control actuator.

Even a slight leak in the air intake system can cause seri-
ous incidents.

Do not shock or jar the camshaft position sensor (PHASE),
crankshaft position sensor (POS).
PBIB1164E
PBIB1512E
PBIB0090E
MEF040D

EC-490
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PREPARATION

PREPARATIONPFP:00002
Special Service ToolsEBS010WK
Tool number
Tool nameDescription
KV10117100
Heated oxygen
sensor wrenchLoosening or tightening heated oxygen sensor
with 22 mm (0.87 in) hexagon nut
KV10114400
Heated oxygen
sensor wrenchLoosening or tightening heated oxygen sensor
a: 22 mm (0.87 in)
EG17650301
Radiator cap tester
adapterAdapting radiator cap tester to radiator cap and
radiator filler neck
a: 28 (1.10) dia.
b: 31.4 (1.236) dia.
c: 41.3 (1.626) dia.
Unit: mm (in)
KV109E0010
Break-out boxMeasuring ECM signals with a circuit tester
KV109E0080
Y-cable adapterMeasuring ECM signals with a circuit tester
S-NT379
S-NT636
S-NT564
NT825
NT826

PREPARATION
EC-491
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Commercial Service ToolsEBS010WL
Tool name Description Description
Quick connector
releaseRemoving fuel tube quick connectors in engine
room
(Available in SEC. 164 of PARTS CATALOG: Part
No. 16441 6N210)
Fuel filler cap adapter Checking fuel tank vacuum relief valve opening
pressure
Socket wrench Removing and installing engine coolant
temperature sensor
Oxygen sensor thread
cleaner
ie: (J-43897-18)
(J-43897-12)Reconditioning the exhaust system threads
before installing a new oxygen sensor. Use with
anti-seize lubricant shown below.
a: 18 mm diameter with pitch 1.5 mm for
Zirconia Oxygen Sensor
b: 12 mm diameter with pitch 1.25 mm for
Titania Oxygen Sensor
Anti-seize lubricant
i.e.: (Permatex
TM
133AR or equivalent
meeting MIL
specification MIL-A-
907)Lubricating oxygen sensor thread cleaning tool
when reconditioning exhaust system threads.
PBIC0198E
S-NT653
S-NT705
AEM488
S-NT779

EC-496
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ENGINE CONTROL SYSTEM

System ChartEBS010WO
*1: This sensor is not used to control the engine system under normal conditions.
*2: This input signal is sent to the ECM through CAN communication line.
*3: This output signal is sent from the ECM through CAN communication line.
*4: With ESP models.
*5: Without ESP models.
Multiport Fuel Injection (MFI) SystemEBS010WP
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM through CAN communication line.Input (Sensor) ECM Function Output (Actuator)

Camshaft position sensor (PHASE)

Crankshaft position sensor (POS)

Mass air flow sensor

Engine coolant temperature sensor

Heated oxygen sensor 1

Throttle position sensor

Accelerator pedal position sensor

Park/neutral position (PNP) switch

Intake air temperature sensor

Power steering pressure sensor

Ignition switch

Battery voltage

Knock sensor

Refrigerant pressure sensor

Stop lamp switch

Heated oxygen sensor 2*1

TCM (Transmission control module)*2

ESP/TCS/ABS control unit*2 *4

ABS actuator and electric unit
(control unit)*2 *5

Air conditioner switch

Wheel sensor*2

Electrical load signalFuel injection & mixture ratio control Fuel injector
Electronic ignition system Power transistor
Fuel pump control Fuel pump relay
On board diagnostic system
MI (On the instrument panel)*
3
Heated oxygen sensor 1 heater control Heated oxygen sensor 1 heater
Heated oxygen sensor 2 heater control Heated oxygen sensor 2 heater
EVAP canister purge flow controlEVAP canister purge volume control
solenoid valve
Air conditioning cut control Air conditioner relay
Cooling fan control Cooling fan relay
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed*
3 and piston position
Fuel injection & mixture
ratio controlFuel injector Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Heated oxygen sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch Gear position
Knock sensor Engine knocking condition
Battery
Battery voltage*
3
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
Wheel sensor*
2Vehicle speed
Air conditioner switch Air conditioner operation

ENGINE CONTROL SYSTEM
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*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The 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 COMPENSATION
In addition, the amount of fuel injected is compensated to improve engine performance under various operat-
ing conditions as listed below.


During warm-up

When starting the engine

During acceleration

Hot-engine operation

When selector lever is changed from N to D (A/T models)

High-load, high-speed operation


During deceleration

During high engine speed operation
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better reduce CO, HC and NOx emissions. This system uses
heated oxygen sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The
ECM adjusts the injection pulse width according to the sensor voltage signal. For more information about
heated oxygen sensor 1, refer to EC-176
. This maintains the mixture ratio within the range of stoichiometric
(ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the three way catalyst (manifold). Even if the switching
characteristics of heated oxygen sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal
from heated oxygen sensor 2.
Open Loop Control
The 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.

Deceleration and acceleration

High-load, high-speed operation

Malfunction of heated oxygen sensor 1 or its circuit

Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature

High engine coolant temperature

During warm-up

After shifting from N to D (A/T models)

When starting the engine
PBIB0121E

EC-498
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ENGINE CONTROL SYSTEM

MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from heated oxygen
sensor 1. 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 controlled as orig-
inally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
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 “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from heated oxygen sensor 1 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.
“Long term fuel trim” 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.
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycle according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all four cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The four injectors will then receive the signals two times for each engine cycle.
This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
FUEL SHUT-OFF
Fuel to each cylinder is cut off during deceleration or operation of the engine at excessively high speeds.
SEF337W

ENGINE CONTROL SYSTEM
EC-499
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Electronic Ignition (EI) SystemEBS010WQ
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The ignition timing is controlled by the ECM to maintain the best air-
fuel ratio for every running condition of the engine. The ignition tim-
ing 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. Computing this information, ignition
signals are transmitted to the power transistor.
e.g., N: 1,800 rpm, Tp: 1.50 msec
A °BTDC
During the following conditions, the ignition timing is revised by the
ECM according to the other data stored in the ECM.

At starting

During warm-up

At idle

At low battery voltage

During 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 ControlEBS010WR
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
2 and piston position
Ignition timing
controlPower transistor Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Knock sensor Engine knocking
Park/neutral position (PNP) switch Gear position
Battery
Battery voltage*
2
Wheel sensor*1Vehicle speed
SEF742M
Sensor Input Signal to ECM ECM function Actuator
Air conditioner switch Air conditioner ON signal
Air conditioner
cut controlAir conditioner relay Throttle position sensor Throttle valve opening angle
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed*
2
Engine coolant temperature sensor Engine coolant temperature
Battery
Battery voltage*
2
Refrigerant pressure sensor Refrigerant pressure
Power steering pressure sensor Power steering operation
Wheel sensor*
1Vehicle speed

EC-500
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ENGINE CONTROL SYSTEM

SYSTEM DESCRIPTION
This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.

When the accelerator pedal is fully depressed.

When cranking the engine.

At high engine speeds.

When the engine coolant temperature becomes excessively high.

When operating power steering during low engine speed or low vehicle speed.

When engine speed is excessively low.

When refrigerant pressure is excessively low or high.
Fuel Cut Control (at No Load and High Engine Speed)EBS010WS
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
If the engine speed is above 1,800 rpm under no load (for example, the shift position is neutral and engine
speed is 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 be operated until the engine speed reaches 1,500 rpm, then fuel cut will be cancelled.
NOTE:
This function is different from deceleration control listed under Multiport Fuel Injection (MFI) System, EC-496
.
CAN Communication UnitEBS010WT
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
Sensor Input Signal to ECM ECM function Actuator
Park/neutral position (PNP) switch Neutral position
Fuel cut control Fuel injector Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed
Wheel sensor* Vehicle speed

ENGINE CONTROL SYSTEM
EC-503
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M/T MODELS WITH ESP
System Diagram
Input/output Signal Chart
T: Transmit R: Receive
*1: YD engine models only
*2: QR engine models only
PKIA6459E
Signals ECMESP/TCS/ABS
control unitSteering angle
sensor4WD control
unitCombination
meter
Stop lamp switch signal T R
Engine speed signal T R R R
Engine coolant temperature signal TR
Accelerator pedal position signal T R R
A/C switch signal*
1RT
A/C compressor feedback signal*
2TR
Vehicle speed signalTRR
RT
ABS warning lamp signal T R
Brake warning lamp signal T R
SLIP indicator lamp signal T R
ESP OFF indicator lamp signal T R
4WD warning lamp signalTR
4WD mode indicator lamp signalTR
Parking brake switch signalRT
MI signal TR
Glow indicator lamp signal*
1TR
Steering angle sensor signal R T