+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)
DESCRIPTIONNLEC0017Input/Output Signal ChartNLEC0017S01
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-35.
Evaporative Emission System
DESCRIPTIONNLEC0018
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.
EVAP canister purge volume control solenoid valve is controlled by ECM. When the engine operates, the flow
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTION
QG18DE
Air Conditioning Cut Control (Cont'd)
EC-39
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
INSPECTIONNLEC0019EVAP CanisterNLEC0019S01Check 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)NLEC0019S031. 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
NLEC0019S07Refer to EC-337.
Checking EVAP Vapour LinesNLEC0019S131. 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
DESCRIPTION
QG18DE
Evaporative Emission System (Cont'd)
EC-40
SEF094Y
SEF214Y
Fuel Pressure ReleaseNLEC0024Before disconnecting fuel line, release fuel pressure from fuel
line to eliminate danger.
WITH CONSULT-IINLEC0024S011. 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-IINLEC0024S021. 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 CheckNLEC0025+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 PROCEDUREQG18DE
Fuel Pressure Release
EC-43
If results are unsatisfactory, perform Fuel Pressure Regulator
Check, EC-44.
SEF718B
Fuel Pressure Regulator CheckNLEC00261. 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 INSTALLATIONNLEC00271. 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 PROCEDUREQG18DE
Fuel Pressure Regulator Check
EC-44
SEF166Y
PreparationNLEC0592+Make sure that the following parts are in good order.
a)Battery
b)Ignition system
c)Engine oil and coolant levels
d)Fuses
e)ECM harness connector
f)Vacuum hoses
g)Air intake system
(Oil filler cap, oil level gauge, etc.)
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 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 PROCEDUREQG18DE
How to Check Idle Speed and Ignition Timing (Cont'd)
EC-47
10 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. Set ªHeated oxygen sensor 1 monitor (front)º in the Diagnostic Test Mode II. Refer to EC-73.
4. Run engine at about 2,000 rpm for about 2 minutes under no-load.
5. Maintain engine at 2,000 rpm under no-load and check that MI goes on more than five times within 10 seconds.
OK or NG
OK©INSPECTION END
NG©GO TO 11.
11 DETECT MALFUNCTIONING PART
Check the following.
1. Check fuel pressure regulator. Refer to EC-44.
2. Check mass air flow sensor and its circuit. Refer to EC-154.
3. Check injector and its circuit. Refer to EC-494.
Clean or replace if necessary.
4. Check engine coolant temperature sensor and its circuit. Refer to EC-169.
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.
12 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-184.
Continuity should exist.
OK or NG
OK©GO TO 14.
NG©GO TO 13.
13 REPAIR OR REPLACE
Repair or replace harness between ECM and heated oxygen sensor 1 (front).
©GO TO 5.
BASIC SERVICE PROCEDUREQG18DE
Inspection Procedure (Cont'd)
EC-53
16 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 5.
NG©GO TO 17.
17 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-44.
+Check mass air flow sensor and its circuit. Refer to EC-154.
+Check injector and its circuit. Refer to EC-494.
Clean or replace if necessary.
+Check engine coolant temperature sensor and its circuit. Refer to EC-169.
+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 5.
BASIC SERVICE PROCEDUREQG18DE
Inspection Procedure (Cont'd)
EC-56
2) 1st trip diagnostic trouble codes
3) Freeze frame data
4) 1st trip freeze frame data
5) System readiness test (SRT) codes
6) Test values
7) Distance traveled while MI is activated.
8) Others
WORK SUPPORT MODENLEC0034S04
WORK ITEM CONDITION USAGE
TP SW/TP SEN IDLE POSI ADJ+FOLLOW THE BASIC INSPECTION INSTRUCTION IN
THE SERVICE MANUAL.When adjusting the idle throttle
position
FUEL PRESSURE RELEASE+FUEL PUMP WILL STOP BY TOUCHING ªSTARTº
DURING IDLING.
CRANK A FEW TIMES AFTER ENGINE STALLS.When releasing fuel pressure
from fuel line
IDLE AIR VOL LEARN+THE IDLE AIR VOLUME THAT KEEPS THE ENGINE
WITHIN THE SPECIFIED RANGE IS MEMORIZED IN
ECM.When learning the idle air volume
SELF-LEARNING CONT+THE COEFFICIENT OF SELF-LEARNING CONTROL
MIXTURE RATIO RETURNS TO THE ORIGINAL
COEFFICIENT.When clear the coefficient of self-
learnign control value
TARGET IDLE RPM ADJ*+IDLE CONDITION When setting target idle speed
TARGET IGNITION TIMING ADJ*+IDLE CONDITION When adjusting target ignition tim-
ing
After adjustment, confirm target
ignition timing with a timing light.
+If once the ªTARGET IDLE
RPM ADJº has been done, the
Idle Air Volume Learning proce-
dure will not be completed.
*: This function is not necessary in the usual service procedure.
SELF DIAGNOSTIC MODENLEC0034S05DTC and 1st Trip DTCNLEC0034S0501Regarding items of ªDTC and 1st trip DTCº, refer to
ªTROUBLE DIAGNOSIS Ð INDEXº, EC-16.
Freeze Frame Data and 1st Trip Freeze Frame DataNLEC0034S0502
Freeze frame data
item*Description
DIAG TROUBLE
CODE
[PXXXX]+Engine Control component part/control system has a trouble code, it is displayed as ªPXXXXº. (Refer
to ªAlphabetical & P No. Index for DTCº, EC-16.)
FUEL SYS-B1+ªFuel injection system statusº at the moment a malfunction is detected is displayed.
+One mode in the following is displayed.
ªMODE 2º: Open loop due to detected system malfunction
ªMODE 3º: Open loop due to driving conditions (power enrichment, deceleration enrichment)
ªMODE 4º: Closed loop - using oxygen sensor(s) as feedback for fuel control
ªMODE 5º: Open loop - has not yet satisfied condition to go to closed loop
CAL/LD VALUE [%]+The calculated load value at the moment a malfunction is detected is displayed.
COOLANT TEMP [ÉC]
or [ÉF]+The engine coolant temperature at the moment a malfunction is detected is displayed.
L-FUEL TRIM-B1 [%]+ªLong-term fuel trimº at the moment a malfunction is detected is displayed.
+The long-term fuel trim indicates much more gradual feedback compensation to the base fuel sched-
ule than short-term fuel trim.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONQG18DE
CONSULT-II (Cont'd)
EC-85