
ECM Terminals and Reference Value=NLEC0446Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
21 B/P Fuel pump relay[Ignition switch ªONº]
+For 1 second after turning ignition switch ªONº
[Engine is running]0-1V
[Ignition switch ªONº]
+More than 1 second after turning ignition switch
ªONºBATTERY VOLTAGE
(11 - 14V)
FUEL PUMPQG18DE
ECM Terminals and Reference Value
EC-517

CONSULT-II Reference Value in Data Monitor
Mode
NLEC0548Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
LOAD SIGNAL+Ignition switch: ONRear window defogger is operating
and/or lighting switch is on.ON
Rear window defogger is not oper-
ating and lighting switch is not on.OFF
HEATER FAN SW+Ignition switch: ONHeater fan motor is operating. ON
Heater fan motor is not operating. OFF
ECM Terminals and Reference ValueNLEC0549Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
50 L/BElectric load signal
(Load switch)[Engine is running]
+Rear window defogger is operating and/or lighting
switch is onBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Rear window defogger is not operating and lighting
switch is not onApproximately 0V
51 LG/B Heater fan motor switch[Engine is running]
+Heater fan motor is operatingApproximately 0V
[Engine is running]
+Heater fan motor is not operatingApproximately 5V
ELECTRICAL LOAD SIGNALQG18DE
CONSULT-II Reference Value in Data Monitor Mode
EC-535

Fuel Pressure RegulatorNLEC0467
Fuel pressure at idling
kPa (bar, kg/cm2, psi)Vacuum hose is connected Approximately 235 (2.35, 2.4, 34)
Vacuum hose is disconnected Approximately 294 (2.94, 3.0, 43)
Idle Speed and Ignition TimingNLEC0468
Target idle speed* rpm700±50
Air conditioner: ON rpm825 or more
Ignition timing8±2É BTDC
Throttle position sensor idle position V 0.15 - 0.85
*: Under the following conditions:
+Air conditioner switch: OFF
+Electrical load: OFF (Lights, heater fan & rear window defogger)
+Steering wheel: Kept in straight-ahead position
Mass Air Flow SensorNLEC0470
Supply voltage (Heater) VBattery voltage (11 - 14)
Supply voltage (Sensor) VApproximately 5
Output voltage V1.0 - 1.7*
Mass air flow
(Using CONSULT-II or GST) g´m/sec1.0 - 4.0 at idle*
5.0 - 10.0 at 2,500 rpm*
*: Engine is warmed up to normal operating temperature and idling under no-load.
Intake Air Temperature SensorNLEC0480
Temperature ÉC (ÉF) Resistance kW
20 (68) 2.1 - 2.9
80 (176) 0.27 - 0.38
Engine Coolant Temperature SensorNLEC0471
Temperature ÉC (ÉF) Resistance kW
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
Throttle Position SensorNLEC0477
Throttle valve conditions Voltage (V)
Completely closed0.15 - 0.85
Completely open3.5 - 4.7
Heated Oxygen Sensor 1 Heater (Front)NLEC0478
Resistance [at 25ÉC (77ÉF)]W2.3 - 4.3
Heated Oxygen Sensor 2 Heater (Rear)NLEC0483
Resistance [at 25ÉC (77ÉF)]W2.3 - 4.3
SERVICE DATA AND SPECIFICATIONS (SDS)QG18DE
Fuel Pressure Regulator
EC-547

Precautions for Supplemental Restraint System
(SRS) ªAIR BAGº and ªSEAT BELT
PRE-TENSIONERº
NLEC1745The 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 col-
lision. 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:
+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 must be performed
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.
+Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses 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 and CVT
NLEC1332The 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.
PRECAUTIONSSR20DE
Precautions for Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
EC-555

SEF706Y
Engine Fuel & Emission Control System=NLEC1333+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.
PRECAUTIONSSR20DE
Engine Fuel & Emission Control System
EC-556

System ChartNLEC1341
Input (Sensor) ECM Function Output (Actuator)
+Camshaft position sensor
+Crankshaft position sensor (OBD)
+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 (where fitted)
+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
Fuel pump control Fuel pump relay
On board diagnostic systemMalfunction indicator
(On the instrument panel)
EGR control (where fitted)EGR volume control valve (where
fitted)
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
*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 CVT will be sent to ECM.
ENGINE AND EMISSION CONTROL OVERALL SYSTEMSR20DE
System Chart
EC-568

Multiport Fuel Injection (MFI) System
DESCRIPTIONNLEC1342Input/Output Signal ChartNLEC1342S01
Sensor Input Signal to ECMECM func-
tionActuator
Camshaft position sensor Engine speed and piston position
Fuel injec-
tion & mix-
ture ratio
controlInjector 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 SystemNLEC1342S02The 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 CompensationNLEC1342S03In 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
+High-load, high-speed operation
+During deceleration
+During high engine speed operation
+Extremely high engine coolant temperature
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTION
SR20DE
Multiport Fuel Injection (MFI) System
EC-569

Fuel Injection TimingNLEC1342S07
SEF337W
Two types of systems are used.
Sequential Multiport Fuel Injection System
NLEC1342S0701Fuel 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
NLEC1342S0702Fuel 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-offNLEC1342S08Fuel to each cylinder is cut off during deceleration or operation of the engine at excessively high speeds.
Electronic Ignition (EI) System
DESCRIPTIONNLEC1343Input/Output Signal ChartNLEC1343S01
Sensor Input Signal to ECMECM func-
tionActuator
Camshaft position sensor Engine speed and piston position
Ignition tim-
ing controlPower transistor 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
DESCRIPTION
SR20DE
Multiport Fuel Injection (MFI) System (Cont'd)
EC-571