2003 NISSAN ALMERA N16 Engine Control

ENGINE CONTROL SYSTEM
EC-25
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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) SystemEBS00K36
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.
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-26
[QG (WITH 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 ControlEBS00K37
INPUT/OUTPUT SIGNAL CHART
*1: These signals are 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
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-27
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Fuel Cut Control (at No Load and High Engine Speed)EBS00K38
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-23
.
CAN CommunicationEBS00K39
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×
Smart entrance control unit××
Data link connector××
Combination meter××
CAN communication type EC-28, "
Type 1"EC-29, "Ty p e 2"

EC-28
[QG (WITH 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-29
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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-31
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2. 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.
3. Check ignition timing.
Accelerator Pedal Released Position LearningEBS00K3B
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.
Throttle Valve Closed Position LearningEBS00K3C
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.
Idle Air Volume LearningEBS00K3D
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:
●Each time electric throttle control actuator or ECM is replaced.
●Idle speed or ignition timing is out of specification.
MBIB0049E
SEF166Y

EC-36
[QG (WITH EURO-OBD)]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
ON BOARD DIAGNOSTIC (OBD) SYSTEM
PFP:00028
IntroductionEBS00K3F
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: 1st trip DTCs for self-diagnoses concerning SRT items cannot be shown on the GST display.
*2: 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-63
.)
Two Trip Detection LogicEBS00K3G
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. Specific on board diagnostic items will cause the ECM to light up or blink the MI, and store
DTC and Freeze Frame data, even in the 1st trip, as shown below.
×: Applicable —: Not applicable
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.
Emission-related diagnostic information ISO Standard
Diagnostic Trouble Code (DTC) Mode 3 of ISO 15031-5
Freeze Frame data Mode 2 of ISO 15031-5
System Readiness Test (SRT) code Mode 1 of ISO 15031-5
1st Trip Diagnostic Trouble Code (1st Trip DTC) Mode 7 of ISO 15031-5
1st Trip Freeze Frame data
Test values and Test limits Mode 6 of ISO 15031-5
Calibration ID Mode 9 of ISO 15031-5
DTC 1st trip DTCFreeze Frame
data1st trip Freeze
Frame dataSRT code Test value
CONSULT-II×× × × ×—
GST×
×*
1×—××
ECM×
×*
2————
ItemsMI DTC 1st trip DTC
1st trip 2nd trip
1st trip
displaying2nd trip
displaying1st trip
displaying2nd trip
display-
ing BlinkingLighting
upBlinkingLighting
up
Misfire (Possible three way cata-
lyst damage) — DTC: P0300 -
P0304 is being detected×———— —×—
Misfire (Possible three way cata-
lyst damage) — DTC: P0300 -
P0304 is being detected——×——×——
One trip detection diagnoses
(Refer to EC-10
.)—×——×—×—
Except above — — —×—××—

EC-48
[QG (WITH EURO-OBD)]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION
How to Erase DTC ( With CONSULT-II)
The emission related diagnostic information in the ECM can be erased by selecting “ERASE” in the “SELF-
DIAG RESULTS” mode with CONSULT-II.
If DTCs are displayed for both ECM and TCM (Transmission control module), they need to be erased individu-
ally from the ECM and TCM (Transmission control module).
NOTE:
If the DTC is not for A/T related items (see EC-10, "
INDEX FOR DTC" ), skip steps 2 through 4.
1. If the ignition switch stays “ON” after repair work, be sure to turn ignition switch “OFF” once. Wait at least
10 seconds and then turn it “ON” (engine stopped) again.
2. Turn CONSULT-II “ON” and touch “A/T”.
3. Touch “SELF-DIAG RESULTS”.
4. Touch “ERASE”. [The DTC in the TCM (Transmission control module) will be erased.] Then touch “BACK”
twice.
5. Touch “ENGINE”.
6. Touch “SELF-DIAG RESULTS”.
7. Touch “ERASE”. (The DTC in the ECM will be erased.)
How to Erase DTC ( With GST)
The emission related diagnostic information in the ECM can be erased by selecting Mode 4 with GST.
NOTE:
If the DTC is not for A/T related items (see EC-10, "
INDEX FOR DTC" ), skip step 2.
1. If the ignition switch stays “ON” after repair work, be sure to turn ignition switch “OFF” once. Wait at least
10 seconds and then turn it “ON” (engine stopped) again.
SEF966X