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
+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
Inspection ProcedureNJEC0593
1 INSPECTION START
1. Visually check the following:
+Air cleaner clogging
+Hoses and ducts for leaks
+EGR valve operation
+Electrical connectors
+Gasket
+Throttle valve and throttle position sensor operation
2. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
Ensure engine stays below 1,000 rpm.
SEF090Y
3. Open engine hood and run engine at about 2,000 rpm for about 2 minutes under no-load.
SEF977U
4. Make sure that no DTC is displayed with CONSULT-II or GST.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 REPAIR OR REPLACE
Repair or replace components as necessary according to corresponding ªDiagnostic Procedureº.
©GO TO 3.
BASIC SERVICE PROCEDUREQG
Inspection Procedure
EC-47
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
25 PREPARATION FOR ªCOº % CHECK
With CONSULT-II
1. Reconnect ECM harness connector.
2. Turn ignition switch ªONº.
3. Select ªCOOLANT TEMPº in ªACTIVE TESTº mode.
4. Set ªCOOLANT TEMPº to 5ÉC (41ÉF) by touching ªDWNº and ªQdº.
SEF172Y
Without CONSULT-II
1. Disconnect ECM harness connector.
2. Disconnect engine coolant temperature sensor harness connector.
3. Connect a resistor (4.4 kW) between terminals of engine coolant temperature sensor harness connector.
SEF982UA
©GO TO 26.
BASIC SERVICE PROCEDUREQG
Inspection Procedure (Cont'd)
EC-54
26 CHECK ªCOº %
1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
SEF090Y
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed.
SEF978U
3. Check ªCOº %.
Idle CO:3-11%
4.
Without CONSULT-II
After checking CO%,
a. Disconnect the resistor from terminals of engine coolant temperature sensor.
b. Connect engine coolant temperature sensor harness connector to engine coolant temperature sensor.
OK or NG
OK©GO TO 27.
NG©GO TO 28.
BASIC SERVICE PROCEDUREQG
Inspection Procedure (Cont'd)
EC-55
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
SEF217Z
SEF454Y
SEF455Y
Idle Air Volume LearningNJEC0562DESCRIPTIONNJEC0562S01ªIdle Air Volume Learningº is an operation to learn the idle air vol-
ume that keeps each engine within the specific range. It must be
performed under any of the following conditions:
+Each time IACV-AAC valve, throttle body or ECM is replaced.
+Idle speed or ignition timing is out of specification.
PRE-CONDITIONINGNJEC0562S02Before performing ªIdle Air Volume Learningº, make sure that all of
the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are
missed for even a moment.
+Battery voltage: More than 12.9V (At idle)
+Engine coolant temperature: 70 - 99ÉC (158 - 210ÉF)
+PNP switch: ON
+Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, set lighting
switch to the 1st position to light only small lamps.
+Cooling fan motor: Not operating
+Steering wheel: Neutral (Straight-ahead position)
+Vehicle speed: Stopped
+Transmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until ªFLUID
TEMP SEº in ªDATA MONITORº mode of ªA/Tº system indi-
cates less than 0.9V.
For A/T models without CONSULT-II and M/T models, drive
vehicle for 10 minutes.
OPERATION PROCEDURENJEC0562S03With CONSULT-IINJEC0562S03011. Turn ignition switch ªONº and wait at least 1 second.
2. Turn ignition switch ªOFFº and wait at least 10 seconds.
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic ªPRE-CONDITION-
INGº (previously mentioned) are in good order.
5. Turn ignition switch ªOFFº and wait at least 9 seconds.
6. Start the engine and let it idle for at least 28 seconds.
7. Select ªIDLE AIR VOL LEARNº in ªWORK SUPPORTº mode.
8. Touch ªSTARTº and wait 20 seconds.
9. Make sure that ªCMPLTº is displayed on CONSULT-II screen.
If ªINCMPº is displayed, ªIdle Air Volume Learningº will not be
carried out successfully. In this case, find the cause of the
problem by referring to the NOTE below.
10. Rev up the engine two or three times. Make sure that idle
speed and ignition timing are within specifications.
ITEM SPECIFICATION
Idle speed M/T: 700±50 rpm
A/T: 800±50 rpm (in ªPº or ªNº position)
Ignition timing M/T: 8±5É BTDC
A/T: 10±5É BTDC (in ªPº or ªNº position)
Without CONSULT-IINJEC0562S03021. Turn ignition switch ªONº and wait at least 1 second.
BASIC SERVICE PROCEDUREQG
Inspection Procedure (Cont'd)
EC-57