
Engine Fuel & Emission Control System
NEF390 ECM (ECCS-D control module)
lDo not disassemble ECM.lIf 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 problem. Do not replace parts
because of a slight variation.
lWhen ECM is removed for inspection, make sure
to ground the ECM mainframe.WIRELESS EQUIPMENT
lWhen installing C.B. ham radio or a mobile
phone, be sure to observe the following as it
may adversely affect electronic control sys-
tems depending on its installation location.
1) Keep the antenna as far as possible away
from the ECM.
2) Keep the antenna feeder line more than
20 cm (7.9 in) away from the harness of elec-
tronic controls.
Do not let them run parallel for a long dis-
tance.
3) Adjust the antenna and feeder line so that the
standing-wave ratio can be kept small.
4) Be sure to ground the radio to vehicle body.
ECM HARNESS HANDLING
lConnect ECM harness connectors securely.
A poor connection can cause an extremely
high (surge) voltage to develop in coil and
condenser, thus resulting in damage to ICs.
lKeep ECM harness at least 10 cm (3.9 in)
away from adjacent harnesses, to prevent an
ECM system malfunction due to receiving
external noise, degraded operation of ICs,
etc.
lKeep ECM parts and harnesses dry.lBefore removing parts, turn off ignition
switch and then disconnect battery ground
cable. WHEN STARTING
lDo not depress accelerator pedal when
starting.
lImmediately after starting, do not rev up
engine unnecessarily.
lDo not rev up engine just prior to shut-
down. ECM PARTS HANDLING
lHandle mass air flow sensor carefully to avoid
damage.
lDo not disassemble mass air flow sensor.lDo not clean mass air flow sensor with any type
of detergent.
lDo not disassemble No. 1 injection nozzle (built-
in needle lift sensor).
lEven a slight leak in the air intake system can
cause serious problems.
lDo not shock or jar the camshaft position sensor
(TDC). ELECTRONIC FUEL INJECTOR PUMP
lDo not disconnect pump harness connectors
with engine running.
lDo not disassemble or adjust electronic fuel
injection pump, except for the following
parts.
Camshaft position sensor (pump)
Injection timing control valve
Fuel cut solenoid valve BATTERY
lAlways use a 12 volt battery as power
source.
lDo not attempt to disconnect battery cables
while engine is running.
ECM mainframe
PRECAUTIONS AND PREPARATIONCD20T
EC-5

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NCEC0002
The Supplemental Restraint System ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº, used along with a seat
belt, help to reduce the risk or severity of injury to the driver and front passenger in a frontal collision. The
Supplemental Restraint System consists of air bag modules (located in the center of the steering wheel and
on the instrument panel on the passenger side), seat belt pre-tensioners, a diagnosis sensor unit, warning
lamp, wiring harness and spiral cable.
In addition to the supplemental air bag modules for a frontal collision, the supplemental side air bag used
along with the seat belt helps to reduce the risk or severity of injury to the driver and front passenger in a
side collision. The supplemental side air bag consists of air bag modules (located in the outer side of front
seats), satellite sensor, diagnosis sensor unit (one of components of supplemental air bags for a frontal
collision), wiring harness, warning lamp (one of components of supplemental air bags for a frontal collision).
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
lTo 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 must be per-
formed by an authorized NISSAN dealer.
lImproper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system.
lDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses (except ªSEAT BELT PRE-TENSIONERº connector) can be
identified with yellow harness connector (and with yellow harness protector or yellow insulation
tape before the harness connectors).
Precautions for On Board Diagnostic (OBD)
System of Engine
NCEC0003
The 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:
lBe 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.
lBe 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.)
lCertain 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.
lBe 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.
lBe 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 the EGR system or fuel injection
system, etc.
lBe sure to erase the unnecessary malfunction information (repairs completed) from the ECM
before returning the vehicle to the customer.
PRECAUTIONS AND PREPARATIONCD20T
EC-6

Precautions
lBefore connecting or disconnecting the ECM harness
connector, turn ignition switch OFF and disconnect
negative battery terminal. Failure to do so may damage
the ECM because battery voltage is applied to ECM even
if ignition switch is turned off.
lWhen connecting ECM harness connectors, push in
both sides of the connector until you hear a click.
Maneuver the lever until you hear the three connectors
on the inside click. Refer to the figure at left.
lBefore replacing ECM, perform Terminals and Reference
Value inspection and make sure ECM functions properly.
Refer to EC-CD-52.
lIf MI illuminates or blinks irregularly during engine
running, water may have accumulated in fuel filter. Drain
water from fuel filter. If this does not correct the problem,
perform specified trouble diagnostic procedures.
lAfter performing each TROUBLE DIAGNOSIS, perform
ªOVERALL FUNCTION CHECKº or ªDTC (Diagnostic
Trouble Code) CONFIRMATION PROCEDUREº.
The DTC should not be displayed in the ªDTC CONFIR-
MATION PROCEDUREº if the repair is completed. The
ªOVERALL FUNCTION CHECKº should be a good result
if the repair is completed.
SEF289H
SEF881Y
MEF040D
SAT652J
PRECAUTIONS AND PREPARATIONCD20T
EC-7

System Chart
Crankshaft position sensor
(TDC)E
ECM
Control sleeve position sensorE
Fuel temperature sensorE
Mass air flow sensorE
Engine coolant temperature
sensorE
Needle lift sensorE
Accelerator position sensorE
Accelerator position switchE
Air conditioner switchE
Ignition switch (ON & ST POS.)E
Battery voltageE
Vehicle speed sensor or ABS
actuator and electric unit (con-
trol unit)E
Brake switchE
Atmospheric pressure sensorE
EFuel injection controlEElectric governor
EFuel injection timing controlEInjection timing control
valve
EFuel cut controlEFuel cut solenoid valve
EGlow control systemEGlow relay & glow lamp
EOn board diagnostic systemEMalfunction indicator
(On the instrument panel)
EEGR valve controlEEGRC-solenoid valve A & B
ECooling fan controlECooling fan relays
EAir conditioning cut controlEAir conditioner relay
ECooling fan motor controlECooling fan relay
ENGINE AND EMISSION CONTROL OVERALL SYSTEMCD20T
EC-14

Glow Control System
SYSTEM DESCRIPTION
Crankshaft position sensor (TDC)EEngine speed
ECMEGlow relayEGlow plugs
Engine coolant temperature sensorEEngine coolant temperatureEGlow lamp
When coolant temperature is lower than 75ÉC (167ÉF):
lIgnition switch ON
After the ignition switch has been turned to ON, the glow
relay turns ON for a period of time depending on the engine
coolant temperature, allowing current to flow through the
glow plugs.
lStarting
After starting the engine, current will flow through the glow
plugs for 300 seconds, or until the coolant temperature
exceeds 50ÉC (122ÉF).
Fuel Injection System
SYSTEM DESCRIPTION
Three types of fuel injection control are provided to accommodate the engine operating conditions; normal
control, idle control and start control. The ECM determines the appropriate fuel injection control. Under each
control, the amount of fuel injected is compensated to improve engine performance. The ECM performs duty
cycle control on the electric governor (built into the fuel injection pump) according to sensor signals to com-
pensate the amount of fuel injected to the preset value.
START CONTROL
Input/output signal line
Engine coolant temperature sensorEEngine coolant temperature
ECM
EElectric
governorCrankshaft position sensor (TDC)EEngine speed
Control sleeve position sensor
EControl sleeve position
When starting, the ECM adapts the fuel injection system for the
start control. The amount of fuel injected at engine starting is a
preset program value in the ECM. The program is determined by
the engine speed and engine coolant temperature.
For better startability under cool engine conditions, the lower the
coolant temperature becomes, the greater the amount of fuel
injected. The ECM ends the start control when the engine speed
reaches a coolant temperature dependent value.
SEF648S Coolant temperature
getting lower
Engine rpm
Fuel injection volume
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONCD20T
EC-15

ENGINE COOLANT TEMPERATURE COMPENSATION (During driving)
Input/output signal line
Crankshaft position sensor (TDC)EEngine speed
ECM
E
Injection
timing con-
trol valveEngine coolant temperature sensorEEngine coolant temperature
Needle lift sensor
EInjection timing
Control sleeve position sensor
EControl sleeve position
For better exhaust efficiency under cool engine conditions, the
fuel injection timing is controlled within a compensation range
depending on the engine speed, engine coolant temperature and
amount of fuel injected.
ENGINE COOLANT TEMPERATURE COMPENSATION (When starting)
Input/output signal line
Crankshaft position sensor (TDC)EEngine speed
ECM
E
Injection
timing con-
trol valveEngine coolant temperature sensorEEngine coolant temperature
Needle lift sensor
EIgnition timing
For better startability under cool engine conditions, the fuel injec-
tion timing is compensated according to the engine coolant tem-
perature.
SEF652S
Fuel injection
timing compensation
Engine coolant
temperature
Low
High
Engine rpm
SEF651S
Fuel injection
timing compensation
Engine coolant
temperature
High
Engine rpm Low
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONCD20T
Fuel Injection Timing System (Cont'd)
EC-19

CONSULT-II
CONSULT-II INSPECTION PROCEDURE
1. Turn off ignition switch.
2. Connect ªCONSULT-IIº to data link connector for CONSULT-
II.
(Data link connector for CONSULT-II is located behind the
fuse box cover.)
3. Turn on ignition switch.
4. Touch ªSTARTº.
5. Touch ªENGINEº.
6. Perform each diagnostic test mode according to each service
procedure.
For further information, see the CONSULT-II Operation
Manual.
NEF225A Fuse box
Data link connector
for CONSULT-II
PEF895K
PEF216U
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONCD20T
EC-27

ENGINE CONTROL MODULE COMPONENT PARTS/CONTROL SYSTEMS APPLICATION
ItemDIAGNOSTIC TEST MODE
SELF-DIAG-
NOSTIC
RESULTSD ATA
MONITORACTIVE
TEST
ENGINE CONTROL MODULE COMPONENT PARTS
INPUTCamshaft position sensor (PUMP) *1 X *2 X
Mass air flow sensor X X
Engine coolant temperature sensor X X
Control sleeve position sensor X X X
Fuel temperature sensor X X
Vehicle speed sensor or ABS actuator and electric unit
(control unit)XX
Accelerator position sensor X X
Accelerator position switch X
Brake lamp switch X *2 X
Crankshaft position sensor (TDC) X X
Needle lift sensor X X
Ignition switch (start signal) X
Ignition switch (ON signal) X
Air conditioner switch X
Brake switch X
Battery voltage X
OUTPUTInjection timing control valve X X X
Fuel cut solenoid valve X X X
Air conditioner relay X
Glow relay X X
EGRC-solenoid valve X X
Cooling fan relay X X
X: Applicable
*1: Imaginary sensor, which produces secondary engine revolution signal using needle lift sensor pulse.
*2: CONSULT-II may not display, but self-diagnostic results are available with MI.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONCD20T
CONSULT-II (Cont'd)
EC-28