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![NISSAN X-TRAIL 2003 Electronic Repair Manual 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 transmitt NISSAN X-TRAIL 2003 Electronic Repair Manual 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 transmitt](/manual-img/5/57402/w960_57402-1504.png)
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.
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![NISSAN X-TRAIL 2003 Electronic Repair Manual EC-392
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ENGINE CONTROL SYSTEM
Electronic Ignition (EI) System
EBS00BEV
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
The ignition timing is controlled by the ECM to maintain the NISSAN X-TRAIL 2003 Electronic Repair Manual EC-392
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ENGINE CONTROL SYSTEM
Electronic Ignition (EI) System
EBS00BEV
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
The ignition timing is controlled by the ECM to maintain the](/manual-img/5/57402/w960_57402-1505.png)
EC-392
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ENGINE CONTROL SYSTEM
Electronic Ignition (EI) System
EBS00BEV
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 ControlEBS00BEW
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
functionActuator
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
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lWhen the accelerator pedal is fully depressed.
lWhen cranking the engine.
lAt high engine speeds.
lWhen the engine coola NISSAN X-TRAIL 2003 Electronic Repair Manual ENGINE CONTROL SYSTEM
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lWhen the accelerator pedal is fully depressed.
lWhen cranking the engine.
lAt high engine speeds.
lWhen the engine coola](/manual-img/5/57402/w960_57402-1506.png)
ENGINE CONTROL SYSTEM
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lWhen the accelerator pedal is fully depressed.
lWhen cranking the engine.
lAt high engine speeds.
lWhen the engine coolant temperature becomes excessively high.
lWhen operating power steering during low engine speed or low vehicle speed.
lWhen engine speed is excessively low.
lWhen refrigerant pressure is excessively low or high.
Fuel Cut Control (at No Load and High Engine Speed)EBS00BEX
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
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 “Multiport Fuel Injection (MFI) System”,EC-389
.
CAN communicationEBS00BEY
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.
FOR A/T MODELS
System Diagram
Input/Output Signal Chart
T: Transmit R: Receive Sensor Input Signal to ECMECM
functionActuator
Park/neutral position (PNP) switch Neutral position
Fuel cut
controlFuel injectors Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS) Engine speed
Wheel sensor Vehicle speed
SKIA0884E
Signals ECM TCM
Engine speed signal T R
Engine coolant temperature signal T R
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EC-394
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ENGINE CONTROL SYSTEM
FOR M/T MODELS
System Diagram
Input/Output Signal Chart
T: Transmit R: Receive Accelerator pedal position signal T R
A/T self-diagnosis signal R TSignals ECM TCM
SKIA0885E
Signals ECMSteering wheel
angle sensor4WD control unitESP/ TCS / ABS
control unit
Engine speed signal T R R
Accelerator pedal position signal T R
ESP operation signal R R T
TCS operation signal R R T
ABS operation signal R R T
Stop lamp switch signalRT
Steering wheel angle sensor signal T R
ESP-OFFSW signalRT
Wheel speed sensor signalRT
4WD Mode signalTR
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BASIC SERVICE PROCEDURE
EC-395
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BASIC SERVICE PROCEDUREPFP:00018
Idle Speed and Ignition Timing CheckEBS00BEZ
IDLE SPEED
lUsing CONSULT-II
Check idle speed in “DATA MONITOR” mode with CONSULT-II.
IGNITION TIMING
Any of following two methods may be used.
lMethod A
–Attach timing light to loop wire as shown.
–Check ignition timing.
lMethod B
–Remove No. 1 ignition coil.
–Connect No. 1 ignition coil and No. 1 spark plug with suitable
high-tension wire as shown, and attach timing light clamp to this
wire.
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![NISSAN X-TRAIL 2003 Electronic Repair Manual EC-396
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BASIC SERVICE PROCEDURE
–Check ignition timing.
Throttle Valve Closed Position LearningEBS00BF0
DESCRIPTION
“Throttle Valve Closed Position Learning” is an operati NISSAN X-TRAIL 2003 Electronic Repair Manual EC-396
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BASIC SERVICE PROCEDURE
–Check ignition timing.
Throttle Valve Closed Position LearningEBS00BF0
DESCRIPTION
“Throttle Valve Closed Position Learning” is an operati](/manual-img/5/57402/w960_57402-1509.png)
EC-396
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BASIC SERVICE PROCEDURE
–Check ignition timing.
Throttle Valve Closed Position LearningEBS00BF0
DESCRIPTION
“Throttle Valve Closed Position Learning” is an operation to learn the fully closed position of the throttle valve
by monitoring the throttle position sensor output signal. It must be performed each time harness connector of
electric throttle control actuator or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch “ON”.
3. Turn ignition switch “OFF” wait at least 10 seconds.
Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.
Accelerator Pedal Released Position LearningEBS00BLT
DESCRIPTION
“Accelerator Pedal Released Position Learning” is an operation to learn the fully released position of the accel-
erator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time
harness connector of accelerator pedal position sensor or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch “ON” and wait at least 2 seconds.
3. Turn ignition switch “OFF” wait at least 10 seconds.
4. Turn ignition switch “ON” and wait at least 2 seconds.
5. Turn ignition switch “OFF” wait at least 10 seconds.
Idle Air Volume LearningEBS00BF1
DESCRIPTION
“Idle Air Volume Learning” is an operation to learn the idle air volume that keeps each engine within the spe-
cific range. It must be performed under any of the following conditions:
lEach time electric throttle control actuator or ECM is replaced.
lIdle speed or ignition timing is out of specification.
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![NISSAN X-TRAIL 2003 Electronic Repair Manual BASIC SERVICE PROCEDURE
EC-397
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PREPARATION
Before performing “Idle Air Volume Learning”, make sure that all of the following conditions are satisf NISSAN X-TRAIL 2003 Electronic Repair Manual BASIC SERVICE PROCEDURE
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PREPARATION
Before performing “Idle Air Volume Learning”, make sure that all of the following conditions are satisf](/manual-img/5/57402/w960_57402-1510.png)
BASIC SERVICE PROCEDURE
EC-397
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PREPARATION
Before performing “Idle Air Volume Learning”, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.
lBattery voltage: More than 12.9V (At idle)
lEngine coolant temperature: 70 - 100°C (158 - 212°F)
lPNP switch: ON
lElectric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, set lighting switch to the 1st position to light
only small lamps.
lSteering wheel: Neutral (Straight-ahead position)
lVehicle speed: Stopped
lTransmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until “FLUID TEMP SE” in “DATA MONITOR” mode of “A/
T” system indicates less than 0.9V.
For A/T models without CONSULT-II and M/T models, drive vehicle for 10 minutes.
OPERATION PROCEDURE
With CONSULT-II
1. PerformEC-396, "Accelerator Pedal Released Position Learning".
2. PerformEC-396, "
Throttle Valve Closed Position Learning".
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic “PRE-CONDITIONING” (previously mentioned) are in good
order.
5. Select “IDLE AIR VOL LEARN” in “WORK SUPPORT” mode.
6. Touch “START” and wait 20 seconds.
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![NISSAN X-TRAIL 2003 Electronic Repair Manual EC-398
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BASIC SERVICE PROCEDURE
7. Make sure that “CMPLT” is displayed on CONSULT-II screen. If
“INCMP” is displayed, “Idle Air Volume Learning” will not be car-
rie NISSAN X-TRAIL 2003 Electronic Repair Manual EC-398
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BASIC SERVICE PROCEDURE
7. Make sure that “CMPLT” is displayed on CONSULT-II screen. If
“INCMP” is displayed, “Idle Air Volume Learning” will not be car-
rie](/manual-img/5/57402/w960_57402-1511.png)
EC-398
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BASIC SERVICE PROCEDURE
7. Make sure that “CMPLT” is displayed on CONSULT-II screen. If
“INCMP” is displayed, “Idle Air Volume Learning” will not be car-
ried out successfully. In this case, find the cause of the problem
by referring to the “Diagnostic Procedure” below.
8. Rev up the engine two or three times and make sure that idle
speed and ignition timing are within the specifications.
Without CONSULT-II
NOTE:
lIt is better to count the time accurately with a clock.
lIt is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit
has a malfunction.
1. PerformEC-396, "
Accelerator Pedal Released Position Learning".
2. PerformEC-396, "
Throttle Valve Closed Position Learning".
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic “PRE-CONDITIONING” (previously mentioned) are in good
order.
5. Turn ignition switch “OFF” and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MI stops
blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MI goes off.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the
specifications.
13. If idle speed and ignition timing are not within the specification, the result will be incomplete. In this case,
find the cause of the problem by referring to the “Diagnostic Procedure” below.
ITEM SPECIFICATION
Idle speed M/T: 650±50 rpm
A/T: 700±50 rpm (in “P” or “N” position)
Ignition timing M/T: 14±5°BTDC
A/T: 16±5°BTDC (in “P” or “N” position)
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ITEM SPECIFICATION
Idle speed M/T: 650±50 rpm
A/T: 700±50 rpm (in “P” or “N” position)
Ignition timing M/T: 14±5°BTDC
A/T: 16±5°BTDC (in “P” or “N” position)
PBIB0665E