coolant NISSAN X-TRAIL 2003 Electronic Service Manual

ENGINE CONTROL SYSTEM
EC-25
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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-160
. 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-27
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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

EC-28
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ENGINE CONTROL SYSTEM
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)EBS00B0U
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-24
.
CAN communicationEBS00B0V
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 func-
tionActuator
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

EC-32
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BASIC SERVICE PROCEDURE
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-31, "Accelerator Pedal Released Position Learning".
2. PerformEC-31, "
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.
SEF452Y
SEF454Y

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-39
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utive trips. If a 1st trip DTC is stored and a non-diagnostic operation is performed between the 1st and 2nd
trips, only the 1st trip DTC will continue to be stored. For malfunctions that blink or light up the MI during the
1st trip, the DTC and 1st trip DTC are stored in the ECM memory.
Procedures for clearing the DTC and the 1st trip DTC from the ECM memory are described inEC-46, "
HOW
TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION".
For malfunctions in which 1st trip DTCs are displayed, refer toEC-37
. These items are required by legal reg-
ulations to continuously monitor the system/component. In addition, the items monitored non-continuously are
also displayed on CONSULT-II.
1st trip DTC is specified in Mode 7 of ISO 15031-5. 1st trip DTC detection occurs without lighting up the MI
and therefore does not warn the driver of a problem. However, 1st trip DTC detection will not prevent the vehi-
cle from being tested, for example during Inspection/Maintenance (I/M) tests.
When a 1st trip DTC is detected, check, print out or write down and erase (1st trip) DTC and Freeze Frame
data as specified in “Work Flow” procedure Step II, refer toEC-58
. Then perform “DTC Confirmation Proce-
dure” or “Overall Function Check” to try to duplicate the problem. If the malfunction is duplicated, the item
requires repair.
How to Read DTC and 1st Trip DTC
DTC and 1st trip DTC can be read by the following methods.
With CONSULT-II
With GST
CONSULT-II or GST (Generic Scan Tool) Examples: P0340, P0705, P0750, etc.
These DTCs are prescribed by ISO 15031-5.
(CONSULT-II also displays the malfunctioning component or system.)
No Tools
The number of blinks of the MI in the Diagnostic Test Mode II (Self-Diagnostic Results) indicates the DTC.
Example: 0102, 0340 etc.
These DTCs are controlled by NISSAN.
l1st trip DTC No. is the same as DTC No.
lOutput of a DTC indicates a malfunction. However, GST or the Diagnostic Test Mode II do not indi-
cate whether the malfunction is still occurring or has occurred in the past and has returned to nor-
mal. CONSULT-II can identify malfunction status as shown below. Therefore, using CONSULT-II (if
available) is recommended.
A sample of CONSULT-II display for DTC and 1st trip DTC is shown below. DTC or 1st trip DTC of a malfunc-
tion is displayed in SELF-DIAGNOSTIC RESULTS mode of CONSULT-II. Time data indicates how many times
the vehicle was driven after the last detection of a DTC.
If the DTC is being detected currently, the time data will be “0”.
Ifa1sttripDTCisstoredintheECM,thetimedatawillbe“[1t]”.
FREEZE FRMADE DATA AND 1ST TRIP FREEZE FRAME DATA
The ECM records the driving conditions such as fuel system status, calculated load value, engine coolant tem-
perature, short term fuel trim, long term fuel trim, engine speed, vehicle speed, base fuel schedule and intake
air temperature at the moment a malfunction is detected.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data.
The data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT-II or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-II screen, not on the GST. For
details, seeEC-89
.
Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no priority
for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
SEF745C

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-45
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lThe time required for each diagnosis varies with road surface conditions, weather, altitude, individual driv-
ing habits, etc.
Zone A refers to the range where the time, required for the diagnosis under normal conditions*, is the
shortest.
Zone B refers to the range where the diagnosis can still be performed if the diagnosis is not completed
within zone A.
*: Normal conditions refer to the following:
lSea level
lFlat road
lAmbient air temperature: 20 - 30°C(68-86°F)
lDiagnosis is performed as quickly as possible under normal conditions.
Under different conditions [For example: ambient air temperature other than 20 - 30°C(68-86°F)], diag-
nosis may also be performed.
Pattern 1:
lThe engine is started at the engine coolant temperature of-10 to 35°C (14 to 95°F)
(where the voltage between the ECM terminal 93 and ground is 3.0 - 4.3V).
lThe engine must be operated at idle speed until the engine coolant temperature is greater than
70°C(158°F) (where the voltage between the ECM terminal 93 and ground is lower than 1.4V).
Pattern 2:
lWhen steady-state driving is performed again even after it is interrupted, each diagnosis can be con-
ducted. In this case, the time required for diagnosis may be extended.
Pattern 3:
lThe driving pattern outlined in *2 must be repeated at least 3 times.
Pattern 4:
lTests are performed after the engine has been operated for at least 17 minutes.
lThe accelerator pedal must be held very steady during steady-state driving.
lIf the accelerator pedal is moved, the test must be conducted all over again.
*1: Depress the accelerator pedal until vehicle speed is 90 km/h (56 MPH), then release the accelerator pedal
and keep it released for more than 10 seconds. Depress the accelerator pedal until vehicle speed is 90 km/h
(56 MPH) again.
*2: Operate the vehicle in the following driving pattern.
1. Decelerate vehicle to 0 km/h (0 MPH) and let engine idle.
2. Repeat driving pattern shown at right at least 10 times.
–During acceleration, hold the accelerator pedal as steady as
possible.
*3: Checking the vehicle speed with GST is advised.
Suggested Transmission Gear Position for A/T Models
Set the selector lever in the “D” position with the overdrive switch turned ON.
TEST VALUE AND TEST LIMIT (GST ONLY — NOT APPLICABLE TO CONSULT-II)
The following is the information specified in Mode 6 of ISO 15031-5.
The test value is a parameter used to determine whether a system/circuit diagnostic test is “OK” or “NG” while
being monitored by the ECM during self-diagnosis. The test limit is a reference value which is specified as the
maximum or minimum value and is compared with the test value being monitored.
Items for which these data (test value and test limit) are displayed are the same as SRT code items (14 test
items).
These data (test value and test limit) are specified by Test ID (TID) and Component ID (CID) and can be dis-
played on the GST screen.
SEF414S

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-51
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codes can be identified by using the CONSULT-II or GST. A DTC will be used as an example for how to read a
code.
A particular trouble code can be identified by the number of four-digit numeral flashes. The “zero” is indicated
by the number of ten flashes. The length of time the 1,000th-digit numeral flashes on and off is 1.2 seconds
consisting of an ON (0.6-second) - OFF (0.6-second) cycle.
The 100th-digit numeral and lower digit numerals consist of a 0.3-second ON and 0.3-second OFF cycle.
A change from one digit numeral to another occurs at an interval of 1.0-second OFF. In other words, the later
numeral appears on the display 1.3 seconds after the former numeral has disappeared.
A change from one trouble code to another occurs at an interval of 1.8-second OFF.
In this way, all the detected malfunctions are classified by their DTC numbers. The DTC “0000” refers to no
malfunction. (SeeEC-12, "
INDEX FOR DTC")
How to Erase Diagnostic Test Mode II (Self-diagnostic Results)
The DTC can be erased from the back up memory in the ECM by depressing accelerator pedal. Refer toEC-
49, "HOW TO SWITCH DIAGNOSTIC TEST MODE".
lIf the battery is disconnected, the DTC will be lost from the backup memory after approx 24 hours.
lBe careful not to erase the stored memory before starting trouble diagnoses.
DIAGNOSTIC TEST MODE II — HEATED OXYGEN SENSOR 1 MONITOR
In this mode, the MI displays the condition of the fuel mixture (lean or rich) which is monitored by the heated
oxygen sensor 1.
*: Maintains conditions just before switching to open loop.
To check the heated oxygen sensor 1 function, start engine in the Diagnostic Test Mode II and warm it up until
engine coolant temperature indicator points to the middle of the gauge.
Next run engine at about 2,000 rpm for about 2 minutes under no-load conditions. Then make sure that the MI
comes ON more than 5 times within 10 seconds with engine running at 2,000 rpm under no-load.
OBD System Operation ChartEBS00BMA
RELATIONSHIP BETWEEN MI, 1ST TRIP DTC, DTC, AND DETECTABLE ITEMS
lWhen a malfunction is detected for the first time, the 1st trip DTC and the 1st trip freeze frame data are
stored in the ECM memory.
SEF952W
MI Fuel mixture condition in the exhaust gas Air fuel ratio feedback control condition
ON Lean
Closed loop system
OFF Rich
*Remains ON or OFF Any condition Open loop system

EC-54
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
EXPLANATION FOR DRIVING PATTERNS FOR "MISFIRE TION>", "FUEL INJECTION SYSTEM"

Driving pattern B means the vehicle operation as follows:
All components and systems should be monitored at least once by the OBD system.
lThe B counter will be cleared when the malfunction is detected once regardless of the driving pattern.
lThe B counter will be counted up when driving pattern B is satisfied without any malfunction.
lThe MI will go off when the B counter reaches 3. (*2 in “OBD SYSTEM OPERATION CHART”)

Driving pattern C means the vehicle operation as follows:
1. The following conditions should be satisfied at the same time:
Engine speed: (Engine speed in the freeze frame data)±375 rpm
Calculated load value: (Calculated load value in the freeze frame data) x (1±0.1) [%]
Engine coolant temperature (T) condition:
lWhen the freeze frame data shows lower than 70°C(158°F), “T” should be lower than 70°C(158°F).
lWhen the freeze frame data shows higher than or equal to 70°C(158°F), “T” should be higher than or
equal to 70°C(158°F).
Example:
If the stored freeze frame data is as follows:
Engine speed: 850 rpm, Calculated load value: 30%, Engine coolant temperature: 80°C(176°F)
To be satisfied with driving pattern C, the vehicle should run under the following conditions:
Engine speed: 475 - 1,225 rpm, Calculated load value: 27 - 33%, Engine coolant temperature: more than 70°C
(158°F)
lThe C counter will be cleared when the malfunction is detected regardless of (1).
lThe C counter will be counted up when (1) is satisfied without the same malfunction.
lThe DTC will not be displayed after C counter reaches 80.
lThe 1st trip DTC will be cleared when C counter is counted once without the same malfunction after DTC
is stored in ECM.
*4: The DTC and the freeze frame data
will not be displayed any longer after
vehicle is driven 80 times (pattern C)
without the same malfunction. (The
DTC and the freeze frame data still
remain in ECM.)*5: When a malfunction is detected for
the first time, the 1st trip DTC and the
1st trip freeze frame data will be
stored in ECM.*6: The 1st trip DTC and the 1st trip
freeze frame data will be cleared at
the moment OK is detected.
*7: When the same malfunction is
detected in the 2nd trip, the 1st trip
freeze frame data will be cleared.*8: 1st trip DTC will be cleared when
vehicle is driven once (pattern C)
without the same malfunction after
DTC is stored in ECM.

EC-62
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TROUBLE DIAGNOSIS
Fail-safe Chart
EBS00BMJ
The ECM enters fail-safe mode, if any of the following malfunctions is detected due to the open or short circuit.
When the ECM enters the fail-safe mode, the MI illuminates.
Priority Detected items (DTC)
1
lU1000 CAN communication line
lP0102 P0103 P1102 Mass air flow sensor
lP0112 P0113 Intake air temperature sensor
lP0117 P0118 Engine coolant temperature sensor
lP0120 Throttle position sensor
lP0121 Accelerator pedal position sensor
lP0327 P0328 Knock sensor
lP0335 Crankshaft position sensor (POS)
lP0340 Camshaft position sensor (PHASE)
lP0500 Vehicle speed sensor
lP0605 ECM
lP0705 Park/Neutral position (PNP) sensor
lP1706 Park/Neutral position (PNP) switch
2
lP0031 P0032 Heated oxygen sensor 1 heater
lP0037 P0038 Heated oxygen sensor 2 heater
lP0132 P0133 P0134 P1143 P1144 Heated oxygen sensor 1
lP0138 P0139 P1146 P1147 Heated oxygen sensor 2
lP0444 P0445 EVAP canister purge volume control solenoid valve
lP0550 Power steering pressure sensor
lP0650 MI
lP0710-P0725, P0740-P0755, P1705 P1760 A/T related sensors and solenoid valves
lP1065 ECM power supply
lP 1111 I n t a k e v a l v e ti m i n g c o n t r o l s o le n o i d v a l v e
lP1122 Electric throttle control function
lP1123 Throttle control motor relay
lP1212 ESP/TCS/ABS communication line
lP1805 Brake switch
3
lP0011 Intake valve timing control
lP0171 P0172 Fuel injection system function
lP0300 - P0304 Misfire
lP0420 Three way catalyst function
lP0731-P0734 A/T function
lP1121 Electric throttle control actuator
lP1217 Engine over temperature (OVERHEAT)
DTC No. Detected items Engine operating condition in fail-safe mode
P0102
P0103
P1102Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.

TROUBLE DIAGNOSIS
EC-63
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P0117
P0118Engine coolant tempera-
ture sensor circuitEngine coolant temperature will be determined by ECM based on the time after turning
ignition switch “ON” or “START”.
CONSULT-II displays the engine coolant temperature decided by ECM.
ConditionEngine coolant temperature decided (CONSULT-
II display)
Just as ignition switch is turned
ON or Start40°C (104°F)
More than approx. 4 minutes after
ignition ON or Start80°C (176°F)
Except as shown above40 - 80°C (104 - 176°F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cool-
ing fan operates while engine is running.
P0120 Throttle position sensor cir-
cuitECM controls the electric throttle control actuator by regulating the throttle opening to
small range.
Therefore, acceleration will be poor.
Condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration DTC No. Detected items Engine operating condition in fail-safe mode