2003 NISSAN X-TRAIL width

EC-26
[QR (WITH EURO-OBD)]
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 film) 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-27
[QR (WITH EURO-OBD)]
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Electronic Ignition (EI) SystemEBS00B0S
INPUT/OUTPUT SIGNAL CHART
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:1,800rpm,Tp:1.50msec
A°BTDC
During the following conditions, the ignition timing is revised by the
ECM according to the other data stored in the ECM.
lAt starting
lDuring warm-up
lAt idle
lAt low battery voltage
lDuring 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 ControlEBS00B0T
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS)
Engine speed
Piston position
Ignition
timing con-
trolPower 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
Ignition switch Start signal
Knock sensor Engine knocking
Park/neutral position (PNP) switch Gear position
Battery Battery voltage
Wheel sensor Vehicle 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) Engine speed
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Refrigerant pressure sensor Refrigerant pressure
Power steering pressure sensor Power steering operation
Wheel sensor Vehicle speed

TROUBLE DIAGNOSIS
EC-91
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CLSD THL POS
[ON/OFF]´´lIndicates idle position [ON/OFF] com-
puted by ECM according to the acceler-
ator pedal position sensor signal.
AIR COND SIG
[ON/OFF]´´
lIndicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
P/N POSI SW
[ON/OFF]´´
lIndicates [ON/OFF] condition from the
park/neutral position (PNP) switch sig-
nal.
PW/ST SIGNAL
[ON/OFF]´´
l[ON/OFF] condition of the power steer-
ing system (determined by the signal
voltage of the power steering pressure
sensor signal) is indicated.
LOAD SIGNAL
[ON/OFF]´´
lIndicates [ON/OFF] condition from the
electrical load signal.
ON ... Rear window defogger switch is
ON and/or lighting switch is in 2nd posi-
tion.
OFF ... Both rear window defogger
switch and lighting switch are OFF.
IGNITION SW
[ON/OFF]´´
lIndicates [ON/OFF] condition from igni-
tion switch.
HEATER FAN SW
[ON/OFF]´
lIndicates [ON/OFF] condition from the
heater fan switch signal.
BRAKE SW
[ON/OFF]´
lIndicates [ON/OFF] condition from the
stop lamp switch signal.
INJ PULSE-B1
[msec]´
lIndicates the actual fuel injection pulse
width compensated by ECM according
to the input signals.lWhen the engine is stopped, a
certain computed value is indi-
cated.
B/FUEL SCHDL
[msec]´
l“Base fuel schedule” indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board cor-
rection.
IGN TIMING
[BTDC]´
lIndicates the ignition timing computed
by ECM according to the input signals.lWhen the engine is stopped, a
certain value is indicated.
A/F ALPHA-B1 [%]´
lThe mean value of the air-fuel ratio
feedback correction factor per cycle is
indicated.
lWhen the engine is stopped, a
certain value is indicated.
lThis data also includes the data
for the air-fuel ratio learning con-
trol.
CAL/LD VALUE [%]
l“Calculated load value” indicates the
value of the current airflow divided by
peak airflow.
MASS AIRFLOW
[g·m/s]
lIndicates the mass airflow computed by
ECM according to the signal voltage of
the mass air flow sensor. Monitored item
[Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSCAN
DIAG
SUP-
PORT
MNTRDescription Remarks

TROUBLE DIAGNOSIS
EC-93
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NOTE:
lAny monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
DATA MONITOR (SPEC) MODE
Monitored Item
NOTE:
lAny monitored item that does not match the vehicle being diagnosed is deleted from the display automatically. Voltage [V]
lVoltage, frequency, duty cycle or pulse
width measured by the probe.
lOnly “#” is displayed if item is
unable to be measured.
lFigures with “#”s are temporary
ones. They are the same figures
as an actual piece of data which
was just previously measured. Frequency
[msec], [Hz] or [%]
DUTY-HI
DUTY-LOW
PLS WIDTH-HI
PLS WIDTH-LOW
CAN COMM
[OK/NG]´
lIndicates the communication condition
of CAN communication line.lThese items are not displayed in
"SELECTION FROM MENU"
mode. CANCIRC1
[OK/UNKWN]´
CANCIRC2
[OK/UNKWN]´
CANCIRC3
[OK/UNKWN]´
CANCIRC4
[OK/UNKWN]´
CANCIRC5
[OK/UNKWN]´ Monitored item
[Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSCAN
DIAG
SUP-
PORT
MNTRDescription Remarks
Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
ENG SPEED [rpm]´
lIndicates the engine speed computed
from the signal of the crankshaft position
sensor (POS).
MAS A/F SE-B1 [V]´´
lThe signal voltage of the mass air flow
sensor specification is displayed.lWhen engine is running specification
range is indicated.
B/FUEL SCHDL
[msec]
l“Base fuel schedule” indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board cor-
rection.
lWhen engine is running specification
range is indicated.
A/F ALPHA-B1 [%]´
lThe mean value of the air-fuel ratio feed-
back correction factor per cycle is indi-
cated.lWhen engine is running specification
range is indicated.
lThis data also includes the data for the
air-fuel ratio learning control.

TROUBLE DIAGNOSIS - SPECIFICATION VALUE
EC-103
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TROUBLE DIAGNOSIS - SPECIFICATION VALUEPFP:00031
DescriptionEBS00B1J
The specification (SP) value indicates the tolerance of the value that is displayed in “DATA MONITOR (SPEC)”
mode of CONSULT-II during normal operation of the Engine Control System. When the value in “DATA MONI-
TOR (SPEC)” mode is within the SP value, the Engine Control System is confirmed OK. When the value in
“DATA MONITOR (SPEC)” 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
MI.
The SP value will be displayed for the following three items:
lB/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board cor-
rection)
lA/F ALPHA-B1 (The mean value of air-fuel ratio feedback correction factor per cycle)
lMAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing ConditionEBS00B1K
lVehicle driven distance: More than 5,000 km (3,017 miles)
lBarometric pressure: 98.3 - 104.3 kPa (0.983 - 1.043 bar, 1.003 - 1.064 kg/cm2, 14.25 - 15.12 psi)
lAtmospheric temperature: 20 - 30°C(68-86°F)
lEngine coolant temperature: 75 - 95°C (167 - 203°F)
lTransmission: Warmed-up*1
lElectrical load: Not applied*2
lEngine speed: Idle
*1: For A/T models with CONSULT-II, after the engine is warmed up to normal operating temperature, drive
vehicle until “FLUID TEMP SE” (A/T fluid temperature sensor signal) indicates more than 60°C (140°F).
For A/T models without CONSUT-II and M/T models, after the engine is warmed up to normal operating tem-
perature, drive vehicle for 5 minutes.
*2: Rear window defogger switch, air conditioner switch, lighting switch are “OFF”. Steering wheel is straight
ahead.
Inspection ProcedureEBS00B1L
NOTE:
Perform “DATA MONITOR (SPEC)” mode in maximum scale display.
1. PerformEC-412, "
Basic Inspection".
2. Confirm that the testing conditions indicated above are met.
3. Select “B/FUEL SCHDL”, “A/F ALPHA-B1” and “MAS A/F SE-
B1” in “DATA MONITOR (SPEC)” mode with CONSULT-II.
4. Make sure that monitor items are within the SP value.
5. If NG, go toEC-104, "
Diagnostic Procedure".
SEF601Z

EC-266
[QR (WITH EURO-OBD)]
DTC P1111 IVT CONTROL SOLENOID VALVE
DTC P1111 IVT CONTROL SOLENOID VALVE
PFP:23796
Component DescriptionEBS00B7P
Intake valve timing control solenoid valve is activated by ON/OFF
pulse duty (ratio) signals from the ECM.
The intake valve timing control solenoid valve changes the oil
amount and direction of flow through intake valve timing control unit
or stops oil flow.
The longer pulse width advances valve angle.
The shorter pulse width retards valve angle.
When ON and OFF pulse widths become equal, the solenoid valve
stops oil pressure flow to fix the intake valve angle at the control
position.
CONSULT-II Reference Value in Data Monitor ModeEBS00B7Q
Specification data are reference values.
ECM Terminals and Reference ValueEBS00B7R
Specification data are reference values and are measured between each terminal and body 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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
On Board Diagnosis LogicEBS00B7S
PBIB0195E
MONITOR ITEM CONDITION SPECIFICATION
INT/V SOL (B1)
lEngine: After warming up
lShift lever: N
lAir conditioner switch: OFF
lNo-loadIdle 0% - 2%
When revving engine up to 2,000 rpm
quicklyApprox. 0% - 50%
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
107 Y/RIntake valve timing
control solenoid valve[Engine is running]
lWarm-up condition
lIdle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
lWarm-up condition
lWhen revving engine up to 2,000 rpm quicklyApproximately 4V - BATTERY
VOLTAGE (11 - 14V)
PBIB0532E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P 1111
1111Intake valve timing con-
trol solenoid valve cir-
cuitAn improper voltage is sent to the ECM
through intake valve timing control solenoid
valve.
lHarness or connectors
(Intake valve timing control solenoid
valve circuit is open or shorted.)
lIntake valve timing control solenoid valve

EC-390
[QR (WITHOUT EURO-OBD)]
ENGINE CONTROL SYSTEM
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.

lDuring warm-up
lWhen starting the engine
lDuring acceleration
lHot-engine operation
lWhen selector lever is changed from “N” to “D”
lHigh-load, high-speed operation

lDuring deceleration
lDuring 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 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 heated
oxygen sensor 1, refer toEC-490
. 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.
lDeceleration and acceleration
lHigh-load, high-speed operation
lMalfunction of heated oxygen sensor 1 or its circuit
lInsufficient activation of heated oxygen sensor 1 at low engine coolant temperature
lHigh engine coolant temperature
lDuring warm-up
lAfter shifting from “N” to “D”
lWhen starting the engine
PBIB0121E

ENGINE CONTROL SYSTEM
EC-391
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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 film) 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