Fuel Injection Control System
DESCRIPTIONNJEC0612System DescriptionNJEC0612S01Three types of fuel injection control are provided to accommodate 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.
Pulse signals are exchanged between ECM and electronic control fuel injection pump (control unit is built-in).
The fuel injection pump control unit performs duty control on the spill valve (built into the fuel injection pump)
according to the input signals to compensate the amount of fuel injected to the preset value.
Start ControlNJEC0612S02Input/Output Signal ChartNJEC0612S0201
Sensor Input Signal to ECM ECM Function Actuator
Engine coolant temperature sensor Engine coolant temperature
Fuel injection
control (start
control)Electronic control fuel
injection pump Crankshaft position sensor (TDC) Engine speed
Ignition switch Start signal
SEF648S
When the ECM receives a start signal from the ignition switch, 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 the specific value,
and shifts the control to the normal or idle control.
Idle ControlNJEC0612S03Input/Output Signal ChartNJEC0612S0301
Sensor Input Signal to ECM ECM Function Actuator
Engine coolant temperature sensor Engine coolant temperature
Fuel injection
control (Idle con-
trol)Electronic control fuel
injection pump Crankshaft position sensor (TDC) Engine speed
Battery Battery voltage
Accelerator position switch Idle position
Vehicle speed sensor Vehicle speed
Air conditioner switch Air conditioner signal
When the ECM determines that the engine speed is at idle, the fuel injection system is adapted for the idle
control. The ECM regulates the amount of fuel injected corresponding to changes in load applied to the engine
to keep engine speed constant. The ECM also provides the system with a fast idle control in response to the
engine coolant temperature signal.
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONYD
Fuel Injection Control System
EC-610
DTC and MI Detection LogicNJEC0626When a malfunction is detected, the malfunction (DTC) is stored in the ECM memory.
The MI will light up each time the ECM detects malfunction. For diagnostic items causing the MI to light up,
refer to ªTROUBLE DIAGNOSIS Ð INDEXº, EC-596.
Diagnostic Trouble Code (DTC)NJEC0627HOW TO READ DTCNJEC0627S01The DTC can be read by the following methods.
Without CONSULT-II
ECM displays the DTC by a set of four digit numbers with MI illumination in the diagnostic test mode II (Self-
diagnostic results). Example: 0103, 0807, 1002, etc.
With CONSULT-II
CONSULT-II displays the DTC in ªSELF-DIAG RESULTSº mode. Examples: P0115, P0571, P1202, etc.
These DTCs are prescribed by ISO15031-6.
(CONSULT-II also displays the malfunctioning component or system.)
+Output of the trouble code means that the indicated circuit has a malfunction. However, in the Mode
II it does not indicate whether the malfunction is still occurring or occurred in the past and returned
to normal.
CONSULT-II can identify them. Therefore, using CONSULT-II (if available) is recommended.
HOW TO ERASE DTCNJEC0627S02How to Erase DTC (With CONSULT-II)NJEC0627S02011. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
5 seconds and then turn it ªONº (engine stopped) again.
2. Touch ªENGINEº.
3. Touch ªSELF-DIAG RESULTSº.
4. Touch ªERASEº. (The DTC in the ECM will be erased.)
SEF246Z
The emission related diagnostic information in the ECM can be erased by selecting ªERASEº in the ªSELF-
DIAG RESULTSº mode with CONSULT-II.
How to Erase DTC (Without CONSULT-II)NJEC0627S02021. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
5 seconds and then turn it ªONº (engine stopped) again.
2. Change the diagnostic test mode from Mode II to Mode I by using the data link connector. (See EC-629.)
The emission related diagnostic information in the ECM can be erased by changing the diagnostic test mode.
+If the battery is disconnected, the emission-related diagnostic information will be lost after approx.
24 hours.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD
DTC and MI Detection Logic
EC-627
+Erasing the emission-related diagnostic information using CONSULT-II is easier and quicker than
switching the diagnostic test mode using the data link connector.
Malfunction Indicator (MI)
DESCRIPTIONNJEC0628
SAT652J
The MI is located on the instrument panel.
1. The MI will light up when the ignition switch is turned ON without the engine running. This is a bulb check.
+If the MI does not light up, refer to EL-184, EL-189, ªWARNING LAMPSº or see EC-831.
2. When the engine is started, the MI should go off.
If the MI remains on, the on board diagnostic system has detected an engine system malfunction.
If MI illuminates or blinks irregularly after starting engine, water may have accumulated in fuel filter.
Drain water from fuel filter. Refer to ªWATER DRAININGº, EC-625.
On Board Diagnostic System FunctionNJEC0628S01The on board diagnostic system has the following three functions.
Diagnostic Test
ModeKEY and ENG.
StatusFunction Explanation of Function
Mode I Ignition switch in
ON position
Engine stopped
BULB CHECK This function checks the MI bulb for damage (blown,
open circuit, etc.).
If the MI does not come on, check MI circuit. (See
EC-831.)
Engine running
MALFUNCTION
WARNINGThis is a usual driving condition. When ECM detects a
malfunction, the MI will light up to inform the driver that
a malfunction has been detected.
Mode II Ignition switch in
ON position
Engine stopped
SELF-DIAGNOSTIC RESULTS This function allows DTCs to be read.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD
Malfunction Indicator (MI)
EC-628
SEF378Y
CONSULT-IINJEC0629CONSULT-II INSPECTION PROCEDURENJEC0629S011. Turn ignition switch OFF.
2. Connect CONSULT-II to data link connector.
(Data link connector is located under the driver side dash
panel.)
SEF995X
SEF320Y
3. Turn ignition switch ON.
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.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD
CONSULT-II
EC-632
ENGINE CONTROL COMPONENT PARTS/CONTROL
SYSTEMS APPLICATION
=NJEC0629S02
ItemDIAGNOSTIC TEST MODE
SELF-DIAG
RESULTSDATA MONI-
TORACTIVE TEST
ENGINE CONTROL COMPONENT PARTS
INPUTEngine coolant temperature sensor X X
Vehicle speed sensor X X
Accelerator position sensor X X
Accelerator position switch X X
Crankshaft position sensor (TDC) X X
Ignition switch (start signal) X
Park/Neutral position (PNP) switch (where fitted) X
Battery voltage X X
Mass air flow sensor X X
Stop lamp switch X X
OUTPUTGlow relayXX
EGR volume control valve X X
Cooling fan relay X X X
X: Applicable
SELF-DIAGNOSTIC MODENJEC0629S03Regarding items detected in ªSELF-DIAG RESULTSº mode,
refer to ªTROUBLE DIAGNOSIS Ð INDEXº, EC-596.
DATA MONITOR MODENJEC0629S04
Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
CKPS´RPM (TDC)
[rpm]jj+The engine speed computed from the
crankshaft position sensor (TDC) signal
is displayed.
CMPS´RPM´PUMP
[rpm]jj+The engine speed computed from the
pulse signal sent from electronic control
fuel injection pump is displayed.
COOLAN TEMP/S
[ÉC] or [ÉF]
jj+The engine coolant temperature (deter-
mined by the signal voltage of the
engine coolant temperature sensor) is
displayed.+When the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine cool-
ant temperature determined by the
ECM is displayed.
VHCL SPEED SE
[km/h] or [mph]jj+The vehicle speed computed from the
vehicle speed sensor signal is dis-
played.
FUEL TEMP SEN
[ÉC] or [ÉF]jj+The fuel temperature (sent from elec-
tronic control fuel injection pump) is dis-
played.
ACCEL POS SEN
[V]jj+The accelerator position sensor signal
voltage is displayed.
OFF ACCEL SW
[ON/OFF]jj+Indicates [ON/OFF] condition from the
accelerator position switch signal.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD
CONSULT-II (Cont'd)
EC-633
ACTIVE TEST MODENJEC0629S05
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
COOLING FAN+Ignition switch: ON
+Operate the cooling fan at
ªLOWº, ªHIº speed and turn
ªOFFº using CONSULT-II.Cooling fan moves at ªLOWº, ªHIº
speed and stops.+Harness and connector
+Cooling fan motor
+Cooling fan relay
EGR VOL
CONT/V+Ignition switch: ON
+Change EGR volume control
valve opening step using CON-
SULT-II.EGR volume control valve makes
an operating sound.+Harness and connector
+EGR volume control valve
GLOW RLY+Ignition switch: ON (Engine
stopped)
+Turn the glow relay ªONº and
ªOFFº using CONSULT-II and
listen to operating sound.Glow relay makes the operating
sound.+Harness and connector
+Glow relay
SEF373Y
SEF707X
REAL TIME DIAGNOSIS IN DATA MONITOR MODENJEC0629S06CONSULT-II has two kinds of triggers and they can be selected by
touching ªSETTINGº in ªDATA MONITORº mode.
1) ªAUTO TRIGº (Automatic trigger):
+The malfunction will be identified on the CONSULT-II screen in
real time.
In other words, DTC will be displayed if the malfunction is
detected by ECM.
At the moment a malfunction is detected by ECM, ªMONITORº
in ªDATA MONITORº screen is changed to ªRecording Data ...
xx%º as shown at left, and the data after the malfunction detec-
tion is recorded. Then when the percentage reached 100%,
ªREAL-TIME DIAGº screen is displayed. If ªSTOPº is touched
on the screen during ª Recording Data ... xx%º, ªREAL-TIME
DIAGº screen is also displayed.
The recording time after the malfunction detection and the
recording speed can be changed by ªTRIGGER POINTº and
ªRecording Speedº. Refer to CONSULT-II OPERATION
MANUAL.
2) ªMANU TRIGº (Manual trigger):
+DTC will not be displayed automatically on CONSULT-II screen
even though a malfunction is detected by ECM.
DATA MONITOR can be performed continuously even though
a malfunction is detected.
Use these triggers as follows:
1) ªAUTO TRIGº
+While trying to detect the DTC by performing the ªDTC Confir-
mation Procedureº, be sure to select to ªDATA MONITOR
(AUTO TRIG)º mode. You can confirm the malfunction at the
moment it is detected.
+While narrowing down the possible causes, CONSULT-II
should be set in ªDATA MONITOR (AUTO TRIG)º mode, espe-
cially in case the incident is intermittent.
When you are inspecting the circuit by gently shaking (or twist-
ing) the suspicious connectors, components and harness in
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD
CONSULT-II (Cont'd)
EC-635
SYSTEM Ð ENGINE CONTROL system
Malfunction
SYMPTOM
Reference page
Feature of symptom, Check pointHARD/NO START/RESTART
(EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
KNOCK/DETONATION
LACK OF POWER
POOR ACCELERATION
HI IDLE
LOW IDLE NO START (with first firing)
NO START (without first firing)
HARD TO START WHEN ENGINE IS COLD
HARD TO START WHEN ENGINE IS HOT
AT IDLE
DURING DRIVING
WHEN DECELERATINGWarranty symptom code AA AB AC AD AE AF
ENGINE CONTROL
Fuel cut system line*a, *c
EC-723
*b 1 1 1 1 *2
Accelerator position sensor circuit *a, *b 1 1 1 EC-685
Crankshaft position sensor (TDC)
circuit*a, *b
111111111EC-695
*d
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*a: Open
*b: Short
*c: Ground short
*d: Noise
*2: Engine runs on after turning ignition switch OFF.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-650
SYSTEM Ð ENGINE CONTROL system
Malfunction
SYMPTOM
Reference page
Feature of symptom, Check pointROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEAT/HIGH ENGINE COOLANT TEMPERATURE
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
ABNORMAL SMOKE COLOR
DEAD BATTERY (UNDER CHARGE)
Malfunction indicator illuminates.
Can be detected by CONSULT-II?BLACK SMOKE
WHITE SMOKEWarranty symptom code AG AH AJ AK AL AM AP HA
ENGINE CONTROL
Fuel cut system line*a, *c 1 1
EC-723
*b*2
Accelerator position sensor circuit *a, *b 1 1 EC-685
Crankshaft position sensor (TDC) circuit*a, *b
1 1 1 1 EC-695
*d
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*a: Open
*b: Short
*c: Ground short
*d: Noise
*2: Engine runs on after turning ignition switch OFF.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-651