2001 NISSAN ALMERA ignition

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NJEC0002The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to NISSAN MODEL N16 is as follows (The compo-
sition varies according to the destination and optional equipment.):
+For a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), front seat
belt pre-tensioners, a diagnoses sensor unit, warning lamp, wiring harness and spiral cable.
+For a side collision
The Supplemental Restraint System consists of front side air bag module (located in the outer side of front
seat), side air bag (satellite) sensor, diagnoses sensor unit (one of components of air bags for a frontal
collision), wiring harness, warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
+To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance should be per-
formed by an authorized NISSAN dealer.
+Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the RS section.
+Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harness can be identified by yellow harness connector.
Precautions for On Board Diagnostic (OBD)
System of Engine and A/T
NJEC0003The ECM has an on board diagnostic system. It will light up the malfunction indicator (MI) to warn the driver
of a malfunction causing emission deterioration.
CAUTION:
+Be sure to turn the ignition switch ªOFFº and disconnect the negative battery terminal before any
repair or inspection work. The open/short circuit of related switches, sensors, solenoid valves, etc.
will cause the MI to light up.
+Be sure to connect and lock the connectors securely after work. A loose (unlocked) connector will
cause the MI to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)
+Certain systems and components, especially those related to OBD, may use a new style slide-
locking type harness connector.
For description and how to disconnect, refer to EL section, ªDescriptionº, ªHARNESS CONNEC-
TORº.
+Be sure to route and secure the harnesses properly after work. The interference of the harness with
a bracket, etc. may cause the MI to light up due to the short circuit.
+Be sure to connect rubber tubes properly after work. A misconnected or disconnected rubber tube
may cause the MI to light up due to the malfunction of fuel injection system, etc.
+Be sure to erase the unnecessary malfunction information (repairs completed) from the ECM and
TCM (Transmission Control Module) before returning the vehicle to the customer.
PRECAUTIONSQG
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
EC-16

SEF706Y
Engine Fuel & Emission Control System=NJEC0004+Always use a 12 volt battery as power source.
+Do not attempt to disconnect battery cables while engine
is running.
+Before connecting or disconnecting the ECM harness
connector, turn ignition switch OFF and disconnect nega-
tive battery terminal. Failure to do so may damage the
ECM because battery voltage is applied to ECM even if
ignition switch is turned off.
SEF707Y
+Do not disassemble ECM.
+If a battery terminal is disconnected, the memory will
return to the ECM value.
The ECM will now start to self-control at its initial value.
Engine operation can vary slightly when the terminal is
disconnected. However, this is not an indication of a prob-
lem. Do not replace parts because of a slight variation.
SEF908W
+When connecting or disconnecting ECM harness
connector, use lever as shown.
When connecting, fasten connector securely with lever
moved until it stops.
SEF291H
+When connecting or disconnecting pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM
pin terminals when connecting pin connectors.
+Securely connect ECM harness connectors.
A Poor connection can cause an extremely high (surge)
voltage to develop in coil and condenser, thus resulting in
damage to ICs.
+Keep ECM harness at least 10 cm (4 in) away from adja-
cent harness, to prevent an ECM system malfunctions due
to receiving external noise, degraded operation of ICs, etc.
+Keep ECM parts and harness dry.
PRECAUTIONSQG
Engine Fuel & Emission Control System
EC-17

System ChartNJEC0013
Input (Sensor) ECM Function Output (Actuator)
+Camshaft position sensor (PHASE)
+Crankshaft position sensor (POS)
+Mass air flow sensor
+Engine coolant temperature sensor
+Heated oxygen sensor 1 (front)
+Ignition switch
+Throttle position sensor
+PNP switch
+Air conditioner switch
+Knock sensor
+EGR temperature sensor*1, *4
+Fuel tank temperature sensor*1, *4
+Battery voltage
+Power steering oil pressure switch
+Vehicle speed sensor
+Intake air temperature sensor
+Heated oxygen sensor 2 (rear)*2
+TCM (Transmission Control Module)*3
+Closed throttle position switch
+Electrical load
+Refrigerant pressure sensorFuel injection & mixture ratio control Injectors
Electronic ignition system Power transistor
Idle air control system IACV-AAC valve
Intake valve timing controlIntake valve timing control sole-
noid valve
Fuel pump control Fuel pump relay
On board diagnostic systemMalfunction indicator
(On the instrument panel)
EGR control*4 EGR volume control valve*4
Heated oxygen sensor 1/2 heater (front/
rear) controlHeated oxygen sensor 1/2 heater
(front/rear)
EVAP canister purge flow controlEVAP canister purge volume con-
trol solenoid valve
Cooling fan control Cooling fan relay
Air conditioning cut control Air conditioner relay
Swirl control valve control*4Swirl control valve control sole-
noid*4
*1: These sensors are not used to control the engine system. They are used only for the on board diagnosis.
*2: Under normal conditions, this sensor is not for engine control operation.
*3: The DTC related to A/T will be sent to ECM.
*4: If so equipped
ENGINE AND EMISSION CONTROL OVERALL SYSTEMQG
System Chart
EC-31

Multiport Fuel Injection (MFI) System
DESCRIPTIONNJEC0014Input/Output Signal ChartNJEC0014S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
Fuel injec-
tion & mix-
ture ratio
controlInjector Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Heated oxygen sensor 1 (front) Density of oxygen in exhaust gas
Throttle position sensorThrottle position
Throttle valve idle position
PNP switch Gear position
Vehicle speed sensor Vehicle speed
Ignition switch Start signal
Air conditioner switch Air conditioner operation
Knock sensor Engine knocking condition
Electrical load Electrical load signal
Battery Battery voltage
Power steering oil pressure switch Power steering operation
Heated oxygen sensor 2 (rear)* Density of oxygen in exhaust gas
* Under normal conditions, this sensor is not for engine control operation.
Basic Multiport Fuel Injection SystemNJEC0014S02The 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 camshaft position sensor and the mass air
flow sensor.
Various Fuel Injection Increase/Decrease CompensationNJEC0014S03In addition, the amount of fuel injected is compensated to improve engine performance under various oper-
ating conditions as listed below.

+During warm-up
+When starting the engine
+During acceleration
+Hot-engine operation
+When selector lever is changed from ªNº to ªDº (A/T models)
+High-load, high-speed operation

+During deceleration
+During high engine speed operation
+During high vehicle speed operation (M/T models)
+Extremely high engine coolant temperature
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONQG
Multiport Fuel Injection (MFI) System
EC-32

Fuel Injection TimingNJEC0014S07
SEF337W
Two types of systems are used.
Sequential Multiport Fuel Injection System
NJEC0014S0701Fuel 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
NJEC0014S0702Fuel 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-offNJEC0014S08Fuel to each cylinder is cut off during deceleration or operation of the engine at excessively high speeds.
Electronic Ignition (EI) System
DESCRIPTIONNJEC0015Input/Output Signal ChartNJEC0015S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
Ignition tim-
ing controlPower transistor Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensorThrottle position
Throttle valve idle position
Vehicle speed sensor Vehicle speed
Ignition switch Start signal
Knock sensor Engine knocking
PNP switch Gear position
Battery Battery voltage
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONQG
Multiport Fuel Injection (MFI) System (Cont'd)
EC-34

System DescriptionNJEC0015S02
SEF742M
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of
the engine. The ignition timing data is stored in the ECM. This data forms the map shown above.
The ECM receives information such as the injection pulse width, crankshaft position sensor signal and cam-
shaft position sensor signal. Computing this information, ignition signals are transmitted to the power transis-
tor.
e.g., N: 1,800 rpm, Tp: 1.50 msec
AÉBTDC
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
+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 Control
DESCRIPTIONNJEC0016Input/Output Signal ChartNJEC0016S01
Sensor Input Signal to ECMECM func-
tionActuator
Air conditioner switch Air conditioner ªONº signal
Air condi-
tioner cut
controlAir conditioner relay PNP switch Neutral position
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
Vehicle speed sensor Vehicle speed
Power steering oil pressure switch Power steering operation
System DescriptionNJEC0016S02This 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.
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONQG
Electronic Ignition (EI) System (Cont'd)
EC-35

SEF094Y
SEF214Y
Fuel Pressure ReleaseNJEC0024Before disconnecting fuel line, release fuel pressure from fuel
line to eliminate danger.
WITH CONSULT-IINJEC0024S011. Start engine.
2. Perform ªFUEL PRESSURE RELEASEº in ªWORK SUP-
PORTº mode with CONSULT-II.
3. After engine stalls, crank it two or three times to release all fuel
pressure.
4. Turn ignition switch OFF.
JEF086Y
WITHOUT CONSULT-IINJEC0024S021. Remove fuse for fuel pump. Refer to fuse block cover for fuse
location.
2. Start engine.
3. After engine stalls, crank it two or three times to release all fuel
pressure.
4. Turn ignition switch OFF and reconnect fuel pump fuse.
JEF087Y
Fuel Pressure CheckNJEC0025+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.
+Do not perform fuel pressure check with system operat-
ing. Fuel pressure gauge may indicate false readings.
1. Release fuel pressure to zero.
2. Disconnect fuel hose between fuel filter and fuel tube (engine
side).
3. Install pressure gauge between fuel filter and fuel tube.
4. Start engine and check for fuel leakage.
5. Read the indication of fuel pressure gauge.
At idle speed:
With vacuum hose connected
Approximately 235 kPa (2.35 bar, 2.4 kg/cm
2,34
psi)
With vacuum hose disconnected
Approximately 294 kPa (2.94 bar, 3.0 kg/cm
2,43
psi)
BASIC SERVICE PROCEDUREQG
Fuel Pressure Release
EC-40

SEF058Y
How to Check Idle Speed and Ignition TimingNJEC0028IDLE SPEEDNJEC0028S05Method A
+Using CONSULT-II
Check idle speed in ªDATA MONITORº mode with CONSULT-
II.
+With GST
Check idle speed in ªMODE 1º with GST.
SEF453Y
Method B (Using Loop wire)
Check the idle speed using loop-wire as shown in the figure.
JEF150Y
JEF438Z
IGNITION TIMINGNJEC0028S06Any of following two methods may be used.
+Method A
a) Attach timing light to loop wire or, combine the three No. 1
ignition coil harnesses and attach the timing light sensor
(attach from above the harness protector) as shown.
b) Check ignition timing.
BASIC SERVICE PROCEDUREQG
How to Check Idle Speed and Ignition Timing
EC-43