2003 NISSAN ALMERA N16 crankshaft

EC-24
[QG (WITH EURO-OBD)]
ENGINE CONTROL SYSTEM
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 the crankshaft position sensor (POS), the camshaft
position sensor (PHASE) 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.

●During warm-up
●When starting the engine
●During acceleration
●Hot-engine operation
●When selector lever is changed from “N” to “D” (A/T models)
●High-load, high-speed operation

●During deceleration
●During 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 to EC-155
. 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.
●Deceleration and acceleration
●High-load, high-speed operation
●Malfunction of heated oxygen sensor 1 or its circuit
●Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature
●High engine coolant temperature
●During warm-up
●After shifting from “N” to “D” (A/T models)
●When starting the engine
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-
PBIB0121E

ENGINE CONTROL SYSTEM
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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"

TROUBLE DIAGNOSIS
EC-63
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Fail-safe ChartEBS00K3N
●When the DTC listed below is detected, the ECM enters fail-safe mode and the MI lights up.
Priority Detected items (DTC)
1
●U1000 U1001 CAN communication line
●P0102 P0103 Mass air flow sensor
●P0112 P0113 Intake air temperature sensor
●P0117 P0118 Engine coolant temperature sensor
●P0221 P0222 P0223 P1223 P1224 P1225 P1226 P1229 Throttle position sensor
●P0226 P0227 P0228 P1227 P1228 Accelerator pedal position sensor
●P0327 P0328 Knock sensor
●P0335 Crankshaft position sensor (POS)
●P0340 Camshaft position sensor (PHASE)
●P0500 Vehicle speed sensor
●P0705 Park/Neutral position (PNP) switch
●P0605 ECM
●P1610-P1615 NATS
●P1706 Park/Neutral position (PNP) switch
2
●P0031 P0032 Heated oxygen sensor 1 heater
●P0037 P0038 Heated oxygen sensor 2 heater
●P0132 P0133 P0134 P1143 P1144 Heated oxygen sensor 1
●P0138 P0139 P1146 P1147 Heated oxygen sensor 2
●P0550 Power steering pressure sensor
●P0710-P0725 P0740-P0755 P1705 P1760 A/T related sensors and solenoid valves
●P1065 ECM power supply
●P 1111 I n ta k e v a l v e t i m i n g c o n t r o l s o l e n o i d v a l v e
●P1122 Electric throttle control function
●P1124 P1126 P1128 Electric throttle control actuator
●P1805 Brake switch
3
●P0011 Intake valve timing control
●P0171 P0172 Fuel injection system function
●P0300 - P0304 Misfire
●P0420 Three way catalyst function
●P0444 EVAP canister purge volume control solenoid valve
●P0731-P0734 A/T function
●P1121 Electric throttle control actuator
●P1217 Engine over temperature (OVERHEAT)
DTC No. Detected items Engine operating condition in fail-safe mode
P0102
P0103Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.

TROUBLE DIAGNOSIS
EC-67
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6.PERFORM IDLE AIR VOLUME LEARNING
Refer to EC-31, "
Idle Air Volume Learning" .
Ye s o r N o
Ye s > > G O T O 7 .
No >> 1. Follow the construction of “Idle Air Volume Learning”.
2. GO TO 4.
7.CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Read idle speed in “DATA MONITOR” mode with CONSULT-II.
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
OK or NG
OK >> GO TO 10.
NG >> GO TO 8.
8.DETECT MALFUNCTIONING PART
Check the following.
●Check camshaft position sensor (PHASE) and circuit. Refer to EC-240 .
●Check crankshaft position sensor (POS) and circuit. Refer to EC-234 .
OK or NG
OK >> GO TO 9.
NG >> 1. Repair or replace.
2. GO TO 4.
9.CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of a incident, but
this is the rarely the case.)
2. Perform initialization of NATS system and registration of NATS ignition key IDs. Refer to EC-49, "
NATS
(Nissan Anti-theft System)" .
>> GO TO 4. Is″Idle Air Volume Learning″ carried out successfully?
M/T: 700 ± 50 rpm
A/T: 800 ± 50 rpm (in “P” or “N” position)
M/T: 700 ± 50 rpm
A/T: 800 ± 50 rpm (in “P” or “N” position)

TROUBLE DIAGNOSIS
EC-69
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15.CHECK IGNITION TIMING AGAIN
1. Run engine at idle.
2. Check ignition timing with a timing light.
OK or NG
OK >>INSPECTION END
NG >> GO TO 16.
16.CHECK TIMING CHAIN INSTALLATION
Check timing chain installation. Refer to EM-47, "
TIMING CHAIN" .
OK or NG
OK >> GO TO 17.
NG >> 1. Repair the timing chain installation.
2. GO TO 4.
17.DETECT MALFUNCTIONING PART
Check the following.
●Check camshaft position sensor (PHASE) and circuit. Refer to EC-240 .
●Check crankshaft position sensor (POS) and circuit. Refer to EC-234 .
OK or NG
OK >> GO TO 18.
NG >> 1. Repair or replace.
2. GO TO 4.
18.CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of a incident, but
this is the rarely the case.)
2. Perform initialization of NATS system and registration of NATS ignition key IDs. Refer to EC-49, "
NATS
(Nissan Anti-theft System)" .
>> GO TO 4. M/T: 8 ± 5° BTDC
A/T: 10 ± 5° BTDC (in “P” or “N” position)

EC-70
[QG (WITH EURO-OBD)]
TROUBLE DIAGNOSIS
Symptom Matrix Chart
EBS00K3P
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel pump circuit 11232 22 3 2EC-381
Fuel pressure regulator system334444444 4EC-34
Injector circuit 11232 22 2EC-375
Evaporative emission system 334444444 4EC-251,
EC-399
Air Positive crankcase ventilation sys-
tem334444444 41EC-402
Incorrect idle speed adjustment 33 1111 1EC-65
Electric throttle control actuator 112332222 2 2EC-276
,
EC-278
,
EC-285
,
EC-291
IgnitionIncorrect ignition timing adjustment33111 11 1EC-65
Ignition circuit 11222 22 2EC-365
Main power supply and ground circuit 22333 33 23EC-110
Mass air flow sensor circuit 11222 22 2EC-134
Engine coolant temperature sensor circuit 11222322312EC-144
Throttle position sensor circuit 12 22222 2EC-199
,
EC-205
,
EC-335
,
EC-341
,
EC-343
,
EC-352
Accelerator pedal position sensor circuit3212 2EC-211
,
EC-218
,
EC-345
Heated oxygen sensor 1 circuit 1232 22 2EC-149
,
EC-155
,
EC-165
,
EC-296
,
EC-302
Knock sensor circuit 2 2 3EC-230
Crankshaft position sensor (POS) circuit 2 2EC-234
Camshaft position sensor (PHASE) circuit 2 2EC-240
Vehicle speed signal circuit 2 3 3 3EC-257