+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 the refrigerant pressure is excessively high or low.
Fuel Cut Control (at no load & high engine
speed)
DESCRIPTIONNJEC0017Input/Output Signal ChartNJEC0017S01
Sensor Input Signal to ECMECM func-
tionActuator
Vehicle speed sensor Vehicle speed
Fuel cut
controlInjectors PNP switch Neutral position
Throttle position sensor Throttle position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS) Engine speed
Camshaft position sensor (PHASE) Engine speed and cylinder number
If the engine speed is above 3,950 rpm with no load, (for example, in Neutral and engine speed over 4,000
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 1,150 rpm, then fuel cut is cancelled.
NOTE:
This function is different from deceleration control listed under ªMultiport Fuel Injection (MFI) Systemº,
EC-32.
Evaporative Emission System
DESCRIPTIONNJEC0018
SEF916WA
The evaporative emission system is used to reduce hydrocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplished by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into the EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not operating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating.
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONQG
Air Conditioning Cut Control (Cont'd)
EC-36
EVAP canister purge volume control solenoid valve is controlled by ECM. When the engine operates, the flow
rate of vapor controlled by EVAP canister purge volume control solenoid valve is proportionally regulated as
the air flow increases.
EVAP canister purge volume control solenoid valve also shuts off the vapor purge line during decelerating and
idling.
SEF917W
INSPECTIONNJEC0019EVAP CanisterNJEC0019S01Check EVAP canister as follows:
1. Block port B. Orally blow air through port A. Check that air
flows freely through port C with check valve resistance.
2. Block port A. Orally blow air through port B. Check that air
flows freely through port C.
SEF918W
SEF943S
Fuel Tank Vacuum Relief Valve (Built into fuel filler cap)NJEC0019S031. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
Pressure:
16.0 - 20.0 kPa (0.16 - 0.20 bar, 0.163 - 0.204 kg/cm
2,
2.32 - 2.90 psi)
Vacuum:
þ6.0 to þ3.5 kPa (þ0.060 to þ0.035 bar, þ0.061 to
þ0.036 kg/cm
2, þ0.87 to þ0.51 psi)
3. If out of specification, replace fuel filler cap as an assembly.
Evaporative Emission (EVAP) Canister Purge Volume
Control Solenoid Valve
NJEC0019S07Refer to EC-369.
Fuel Tank Temperature SensorNJEC0019S08Refer to EC-317 (If so equipped).
Checking EVAP Vapour LinesNJEC0019S131. Visually inspect vapor lines for leaks, cracks, damage, loose
connections, chafing and deterioration.
2. Inspect vacuum relief valve of fuel tank filler cap for clogging,
sticking, etc. Refer to next page.
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONQG
Evaporative Emission System (Cont'd)
EC-37
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
If results are unsatisfactory, perform Fuel Pressure Regulator
Check, EC-41.
SEF718B
Fuel Pressure Regulator CheckNJEC00261. Stop engine and disconnect fuel pressure regulator vacuum
hose from intake manifold.
2. Plug intake manifold with a rubber cap.
3. Connect variable vacuum source to fuel pressure regulator.
4. Start engine and read indication of fuel pressure gauge as
vacuum is changed.
Fuel pressure should decrease as vacuum increases. If results
are unsatisfactory, replace fuel pressure regulator.
JEF088Y
SEF927W
Injector
REMOVAL AND INSTALLATIONNJEC00271. Release fuel pressure to zero.
2. Remove fuel tube assemblies in numerical sequence as
shown in the Figure at left.
3. Expand and remove clips securing fuel injectors.
4. Extract fuel injectors straight from fuel tubes.
+Be careful not to damage injector nozzles during removal.
+Do not bump or drop fuel injectors.
5. Install fuel injectors.
Carefully install O-rings, including the one used with the pres-
sure regulator.
+Lubricate O-rings with a smear of engine oil.
+Be careful not to damage O-rings with service tools or
finger nails or clips. Do not expand or twist O-rings.
+Discard old clips; replace with new ones.
6. Position clips in grooves on fuel injectors.
+Make sure that protrusions of fuel injectors are aligned
with cutouts of clips after installation.
BASIC SERVICE PROCEDUREQG
Fuel Pressure Regulator Check
EC-41
h)Fuel pressure
i)Engine compression
j)EGR valve operation
k)Throttle valve
l)EVAP system
+On models equipped with air conditioner, checks should
be carried out while the air conditioner is ªOFFº.
+When checking idle speed on models equipped with A/T,
ignition timing and mixture ratio, checks should be carried
out while shift lever is in ªPº or ªNº position.
+When measuring ªCOº percentage, insert probe more
than 40 cm (15.7 in) into tail pipe.
+Turn off headlamps, heater blower, rear window defogger.
+On vehicles equipped with daytime light systems, set
lighting switch to the 1st position to light only small
lamps.
+Keep front wheels pointed straight ahead.
+If engine stops immediately after starting or idle condition
is unstable, perform the following to initialize IACV-AAC
valve:
a)Stop engine and wait 9 seconds.
b)Turn ignition ªONº and wait 1 second.
c)Turn ignition ªOFFº and wait 9 seconds.
+Make sure the cooling fan has stopped.
BASIC SERVICE PROCEDUREQG
Preparation (Cont'd)
EC-45
21 CHECK HEATED OXYGEN SENSOR 1 (FRONT) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
6. Running engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.), check that the
monitor fluctuates between ªLEANº and ªRICHº more than 5 times during 10 seconds.
1 time: RICH®LEAN®RICH
2 times: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 62 and ground.
6. Make sure that the voltage fluctuates between 0 to 0.3V and 0.6 to 1.0V more than 5 times during 10 seconds at 2,000
rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©INSPECTION END
NG©GO TO 22.
22 DETECT MALFUNCTIONING PART
Check the following.
1. Check fuel pressure regulator. Refer to EC-41.
2. Check mass air flow sensor and its circuit. Refer to EC-187.
3. Check injector and its circuit. Refer to EC-541.
Clean or replace if necessary.
4. Check engine coolant temperature sensor and its circuit. Refer to EC-201.
5. Check ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 3.
23 CHECK HEATED OXYGEN SENSOR 1 (FRONT) HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect heated oxygen sensor 1 (front) harness connector.
4. Check harness continuity between ECM terminal 62 and heated oxygen sensor 1 (front) harness connector terminal 1.
Refer to Wiring Diagram, EC-216.
Continuity should exist.
OK or NG
OK©GO TO 25.
NG©GO TO 24.
24 REPAIR OR REPLACE
Repair or replace harness between ECM and heated oxygen sensor 1 (front).
©GO TO 3.
BASIC SERVICE PROCEDUREQG
Inspection Procedure (Cont'd)
EC-53
27 CHECK HEATED OXYGEN SENSOR 1 (FRONT) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
6. Maintaining engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.), check that the
monitor fluctuates between ªLEANº and ªRICHº more than 5 times during 10 seconds.
1 time: RICH®LEAN®RICH
2 times: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 62 and ground.
6. Make sure that voltage fluctuates between 0 - 0.3V and 0.6 - 1.0V more than 5 times during 10 seconds at 2,000 rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©GO TO 3.
NG©GO TO 28.
28 DETECT MALFUNCTIONING PART
Check the following.
+Connect heated oxygen sensor 1 (front) harness connectors to heated oxygen sensors 1 (front).
+Check fuel pressure regulator. Refer to EC-41.
+Check mass air flow sensor and its circuit. Refer to EC-187.
+Check injector and its circuit. Refer to EC-541.
Clean or replace if necessary.
+Check engine coolant temperature sensor and its circuit. Refer to EC-201.
+Check ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 3.
BASIC SERVICE PROCEDUREQG
Inspection Procedure (Cont'd)
EC-56
ENGINE CONTROL COMPONENT PARTS/CONTROL
SYSTEMS APPLICATION
NJEC0034S02
ItemDIAGNOSTIC TEST MODE
WORK
SUP-
PORTSELF-DIAGNOSTIC
RESULTS
D ATA
MONI-
TORD ATA
MONI-
TOR
(SPEC)ACTIVE
TESTDTC & SRT
CONFIRMATION
DTC*1FREEZE
FRAME
DATA*2SRT
STA-
TUSDTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUTCamshaft position sensor
(PHASE)XEngine
speed
XEngine
speed
XEngine
speed
X
Crankshaft position sensor
(POS)X*3
Mass air flow sensor X X X
Engine coolant temperature
sensorXXXXX
Heated oxygen sensor 1
(front)X X X X*3 X*3
Heated oxygen sensor 2
(rear)X*3 X X X*3 X*3
Vehicle speed sensorXXXX
Throttle position sensor X X X
Fuel tank temperature sensor X X
EGR temperature sensor*4 X*3 X X
Intake air temperature sensor X*3 X X X
Knock sensor X
Ignition switch (start signal) X X
Closed throttle position
switch*4X*3 X X
Closed throttle position switch
(throttle position sensor sig-
nal)XX
Air conditioner switch X X
Refrigerant pressure sensor X X
Park/Neutral position (PNP)
switchX*3 X X
Power steering oil pressure
switchXX
Electrical load X X
Heater fan switch X X
Battery voltage X X
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONQG
CONSULT-II (Cont'd)
EC-84