2003 NISSAN ALMERA N16 fuel

ENGINE CONTROL SYSTEM
EC-419
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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.
Electronic Ignition (EI) SystemEBS00KED
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
*2: The ECM determines the start signal status by the signals of engine speed and battery voltage.
SEF337W
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed
*2 and piston position
Ignition timing control Power transistor 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
Vehicle speed signal*1Vehicle speed

EC-420
[QG (WITHOUT EURO-OBD)]
ENGINE CONTROL SYSTEM
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 ControlEBS00KEE
INPUT/OUTPUT SIGNAL CHART
*1: These signals are sent to the ECM through CAN communication line.
*2: The ECM determines the start signal status by the signals of engine speed and battery voltage.
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.
SEF742M
Sensor Input Signal to ECM ECM function Actuator
Air conditioner switch
*1Air 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
Vehicle speed signal
*1Vehicle speed

ENGINE CONTROL SYSTEM
EC-421
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Fuel Cut Control (at No Load and High Engine Speed)EBS00KEF
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
If the engine speed is above 3,950 rpm with no load (for example, in neutral and engine speed over 3,950
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-417
.
CAN CommunicationEBS00KEG
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.
CAN COMMUNICATION UNIT
×:ApplicableSensor Input Signal to ECM ECM function Actuator
Park/neutral position (PNP) switch Neutral position
Fuel cut control Fuel injectors Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed
Vehicle speed signal
*1Vehicle speed
Body type Sedan/ 5DH/B/ 3DH/B
Axle2WD
Engine QG18DE QG15DE/QG18DE
Transmission A/T M/T
Brake controlABS
CAN communication unit
ECM××
TCM×
Data link connector××
Smart entrance control unit××
Combination meter××
CAN communication type EC-422, "
Ty p e 1"EC-423, "Type 2"

EC-422
[QG (WITHOUT EURO-OBD)]
ENGINE CONTROL SYSTEM
Ty p e 1
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL CHART
T: Transmit R: Receive
SEL825Y
Signals ECM TCMSmart entrance
control unitCombination meter
Engine speed signal T R
Brake switch signal R T
Rear window defogger signal R T
Heater fan switch signal R T
Air conditioner switch signal R T
MI signal T R
Current gear position signal T R
Engine coolant temperature signal T R
Fuel consumption signal T R
Vehicle speed signal R T
Seat belt reminder signalRT
Headlamp switch signalTR
Flashing indicator signalTR
Engine cooling fan speed signal T R
Child lock indicator signalTR
Door switches state signalTR
A/C compressor signal T R
Accelerator pedal position signal T R
Output shaft revolution signal R T
OD OFF switch signal R T
OD OFF indicator signal T R
A/T self-diagnosis signal R T

ENGINE CONTROL SYSTEM
EC-423
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Ty p e 2
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL CHART
T: Transmit R: Receive
SEL826Y
Signals ECMSmart entrance control
unitCombination meter
Engine speed signal T R
Rear window defogger signal R T
Heater fan switch signal R T
Air conditioner switch signal R T
MI signal T R
Engine coolant temperature signal T R
Fuel consumption signal T R
Vehicle speed signal R T
Seat belt reminder signal R T
Headlamp switch signal T R
Flashing indicator signal T R
Engine cooling fan speed signal T R
Child lock indicator signal T R
Door switches state signal T R
A/C compressor signal T R

BASIC SERVICE PROCEDURE
EC-427
[QG (WITHOUT EURO-OBD)]
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4. Check that all items listed under the topic “PREPARATION” (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 turned ON.
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, “Idle Air Volume Learning” will not be car-
ried out successfully. In this case, find the cause of the incident by referring to the “Diagnostic Procedure”
below.
DIAGNOSTIC PROCEDURE
If idle air volume learning cannot be performed successfully, proceed as follows:
1.Check that throttle valve is fully closed.
2.Check PCV valve operation.
3.Check that downstream of throttle valve is free from air leakage.
4.When the above three items check out OK, engine component parts and their installation condi-
tion are questionable. Check and eliminate the cause of the incident.
It is useful to perform EC-481, "
TROUBLE DIAGNOSIS - SPECIFICATION VALUE" .
5.If any of the following conditions occur after the engine has started, eliminate the cause of the
incident and perform “Idle air volume learning” all over again:
–Engine stalls.
–Erroneous idle.
Fuel Pressure CheckEBS00KEL
FUEL PRESSURE RELEASE
Before disconnecting fuel line, release fuel pressure from fuel line to eliminate danger.
NOTE:
Prepare pans or saucers under the disconnected fuel line because the fuel may spill out. The fuel pres-
sure cannot be completely released because N16 models do not have fuel return system.
With CONSULT-II
1. Turn ignition switch “ON”.
ITEM SPECIFICATION
Idle speed M/T: 700±50 rpm
A/T: 800±50 rpm (in “P” or “N” position)
Ignition timing M/T: 8±5° BTDC
A/T: 10±5° BTDC (in “P” or “N” position)
PBIB0665E

EC-428
[QG (WITHOUT EURO-OBD)]
BASIC SERVICE PROCEDURE
2. Perform “FUEL PRESSURE RELEASE” in “WORK SUPPORT”
mode with CONSULT-II.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel
pressure.
5. Turn ignition switch “OFF”.
Without CONSULT-II
1. Remove fuel pump fuse located in fuse box.
2. Start engine.
3. After engine stalls, crank it two or three times to release all fuel
pressure.
4. Turn ignition switch “OFF”.
5. Reinstall fuel pump fuse after servicing fuel system.
FUEL PRESSURE CHECK
NOTE:
●When reconnecting fuel line, always use new clamps.
●Make sure that clamp screw does not contact adjacent parts.
●Use a torque driver to tighten clamps.
●Use Pressure Gauge to check fuel pressure.
1. Release fuel pressure to zero. Refer to EC-427, "
FUEL PRESSURE RELEASE" .
2. Install the fuel pressure gauge with the fuel pressure check
adapter as shown in the figure.
3. Turn ignition switch “ON”, and check for fuel leakage.
4. Start engine and check for fuel leakage.
5. Read the indication of fuel pressure gauge.
6. If result is unsatisfactory, go to next step.
7. Check the following.
●Fuel hoses and fuel tubes for clogging
●Fuel filter for clogging
●Fuel pump
●Fuel pressure regulator for clogging
If OK, replace fuel pressure regulator.
If NG, repair or replace.
SEF214Y
MBIB0262E
At idling: Approximately 350 kPa
(3.5 bar, 3.57 kg/cm
2 , 51 psi)
MBIB0050E

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-429
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ON BOARD DIAGNOSTIC (OBD) SYSTEMPFP:00028
IntroductionEBS00KEM
The ECM has an on board diagnostic system, which detects malfunctions related to engine sensors or actua-
tors. The ECM also records various emission-related diagnostic information including:
The above information can be checked using procedures listed in the table below.
×: Applicable —: Not applicable
*1: When DTC and 1st trip DTC simultaneously appear on the display, they cannot be clearly distinguished from each other.
The malfunction indicator (MI) on the instrument panel lights up when the same malfunction is detected in two
consecutive trips (Two trip detection logic), or when the ECM enters fail-safe mode. (Refer to EC-441
.)
Two Trip Detection LogicEBS00KEN
When a malfunction is detected for the first time, 1st trip DTC and 1st trip Freeze Frame data are stored in the
ECM memory. The MI will not light up at this stage. <1st trip>
If the same malfunction is detected again during the next drive, the DTC and Freeze Frame data are stored in
the ECM memory, and the MI lights up. The MI lights up at the same time when the DTC is stored. <2nd trip>
The “trip” in the “Two Trip Detection Logic” means a driving mode in which self-diagnosis is performed during
vehicle operation. When the ECM enters fail-safe mode (Refer to EC-441
.), the DTC is stored in the ECM
memory even in the 1st trip.
When there is an open circuit on MI circuit, the ECM cannot warn the driver by lighting MI up when there is
malfunction on engine control system.
Therefore, when electrical controlled throttle and part of ECM related diagnoses are continuously detected as
NG for 5 trips, ECM warns the driver that engine control system malfunctions and MI circuit is open by means
of operating fail-safe function.
The fail-safe function also operates when above diagnoses except MI circuit and demands the driver to repair
the malfunction.
Emission-related Diagnostic InformationEBS00KEO
DTC AND 1ST TRIP DTC
The 1st trip DTC (whose number is the same as the DTC number) is displayed for the latest self-diagnostic
result obtained. If the ECM memory was cleared previously, and the 1st trip DTC did not reoccur, the 1st trip
DTC will not be displayed.
If a malfunction is detected during the 1st trip, the 1st trip DTC is stored in the ECM memory. The MI will not
light up (two trip detection logic). If the same malfunction is not detected in the 2nd trip (meeting the required
driving pattern), the 1st trip DTC is cleared from the ECM memory. If the same malfunction is detected in the
2nd trip, both the 1st trip DTC and DTC are stored in the ECM memory and the MI lights up. In other words,
the DTC is stored in the ECM memory and the MI lights up when the same malfunction occurs in two consec-
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 fail-safe items, the DTC is stored in the ECM memory
even in the 1st trip.
Procedures for clearing the DTC and the 1st trip DTC from the ECM memory are described in EC-430, "
HOW
TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION" .
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 to EC-437
. Then perform “DTC Confirmation Proce-
dure” or “Overall Function Check” to try to duplicate the malfunction. If the malfunction is duplicated, the item
requires repair.
Emission-related diagnostic information
Diagnostic Trouble Code (DTC)
Freeze Frame data
1st Trip Diagnostic Trouble Code (1st Trip DTC)
1st Trip Freeze Frame data
DTC 1st trip DTC Freeze Frame data1st trip Freeze Frame
data
CONSULT-II×× × ×
ECM×
×*
1——
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut