Normal ControlNJEC0612S04Input/Output Signal ChartNJEC0612S0401
Sensor Input Signal to ECM ECM Function Actuator
Crankshaft position sensor (TDC) Engine speedFuel injection
control (Normal
control)Electronic control fuel
injection pump
Accelerator position sensor Accelerator position
SEF649S
The amount of fuel injected under normal driving conditions is determined according to sensor signals. The
crankshaft position sensor (TDC) detects engine speed and the accelerator position sensor detects accelera-
tor position. These sensors send signals to the ECM.
The fuel injection data, predetermined by correlation between various engine speeds and accelerator positions,
are stored in the ECM memory, forming a map. The ECM determines the optimal amount of fuel to be injected
using the sensor signals in comparison with the map.
Maximum Amount ControlNJEC0612S05Input/Output Signal ChartNJEC0612S0501
Sensor Input Signal to ECM ECM Function Actuator
Mass air flow sensor Amount of intake air
Fuel injection
control (Maxi-
mum amount
control)Electronic control fuel
injection pump Engine coolnat temperature sensor Engine coolant temperature
Crankshaft position sensor (TDC) Engine speed
Accelerator position sensor Accelerator position
The maximum injection amount is controlled to an optimum by the engine speed, intake air amount, engine
coolant temperature, and accelerator opening in accordance with the driving conditions.
This prevents the oversupply of the injection amount caused by decreased air density at a high altitude or
during a system failure.
Deceleration ControlNJEC0612S06Input/Output Signal ChartNJEC0612S0601
Sensor Input Signal to ECM ECM Function Actuator
Accelerator position switch Accelerator positionFuel injection
control (Decel-
eration control)Electronic control fuel
injection pump
Crankshaft position sensor (TDC) Engine speed
The ECM sends a fuel cut signal to the electronic control fuel injection pump during deceleration for better
fuel efficiency. The ECM determines the time of deceleration according to signals from the accelerator posi-
tion switch and crankshaft position sensor (TDC).
Fuel Injection Timing Control System
DESCRIPTIONNJEC0613The target fuel injection timing in accordance with the engine speed and the fuel injection amount are recorded
as a map in the ECM beforehand. The ECM and the injection pump control unit exchange signals and per-
form feedback control for optimum injection timing in accordance with the map.
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONYD
Fuel Injection Control System (Cont'd)
EC-506
Air Conditioning Cut Control
DESCRIPTIONNJEC0614Input/Output Signal ChartNJEC0614S01
Sensor Input Signal to ECM ECM Function Actuator
Air conditioner switch Air conditioner ªONº signal
Air conditioner
cut controlAir conditioner relay Accelerator position sensor Accelerator valve opening angle
Vehicle speed sensor Vehicle speed
Engine coolant temperature sensor Engine coolant temperature
System DescriptionNJEC0614S02This system improves acceleration when the air conditioner is used.
When the accelerator pedal is fully depressed, the air conditioner is turned off for a few seconds.
When engine coolant temperature becomes excessively high, the air conditioner is turned off. This continues
until the engine coolant temperature returns to normal.
Fuel Cut Control (at no load & high engine
speed)
DESCRIPTIONNJEC0615Input/Output Signal ChartNJEC0615S01
Sensor Input Signal to ECM ECM Function Actuator
Vehicle speed sensor Vehicle speed
Fuel cut controlElectronic control fuel
injection pump Accelerator position switch Accelerator position
Crankshaft position sensor (TDC) Engine speed
If the engine speed is above 2,800 rpm with no load (for example, in neutral and engine speed over 2,800
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 1,500 rpm, then fuel cut is cancelled.
NOTE:
This function is different from deceleration control listed under ªFuel Injection Control Systemº,
EC-505.
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONYD
Air Conditioning Cut Control
EC-507
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-492.
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-528
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
Electronic control fuel injection
pump circuit*a, *b 1 1
111111111
Ð
*c, *d
Mass air flow sensor circuit*a, *c
111
EC-566
*b
Engine coolant temperature sensor
circuit*a, *b 1 1 1 1 EC-572 *1
Vehicle speed sensor circuit *a, *b 1 EC-593
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*a: Open
*b: Short
*c: Ground short
*d: Noise
*1: Compensation according to engine coolant temperature does not function.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-543
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
Electronic control fuel injection pump
circuit*a, *b 1 1 1
11 Ð
*c, *d 1
Mass air flow sensor circuit*a, *c
1 EC-566
*b 1
Engine coolant temperature sensor cir-
cuit*a, *b 1 1 1 1 1 EC-572 *1
Vehicle speed sensor circuit *a, *b 1 EC-593
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*a: Open
*b: Short
*c: Ground short
*d: Noise
*1: Compensation according to engine coolant temperature does not function.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-544
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-612
*b*2
Accelerator position sensor circuit *a, *b 1 1 EC-577
Crankshaft position sensor (TDC) circuit*a, *b
1 1 1 1 EC-587
*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-546
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
Start signal circuit *a, *b EC-693 *3
Accelerator position switch (Idle) circuit*a, *c
EC-577
*b 1 1 *4
Ignition switch circuit*a
EC-560
*b*5
Power supply for ECM circuit*a
1 1 EC-560
*b
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*a: Open
*b: Short
*c: Ground short
*d: Noise
*3: Start control does not function.
*4: Accelerator position sensor NG signal is output.
*5: Engine does not stop.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-548
TERMI-
NAL
NO.WIRE
COLORITEM CONDITIONDATA (DC Voltage and Pulse
Signal)
204 L Air conditioner relay[Engine is running]
+Air conditioner switch is ªOFFºBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Both air conditioner switch and blower fan
switch are ªONº
(Compressor is operating)Approximately 0.1V
214 W/B Glow relay Refer to ªGlow Control Systemº, EC-677.
218 B Sensors' ground[Engine is running]
+Warm-up condition
+Idle speedApproximately 0V
219 LG/R Cooling fan relay (Low)[Engine is running]
+Cooling fan is not operatingBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Cooling fan is operatingApproximately 0.1V
221 LG/B Cooling fan relay (High)[Engine is running]
+Cooling fan is not operating
+Cooling fan is operating at low speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Cooling fan is operating at high speedApproximately 0.1V
223 WMass air flow sensor
power supply[Ignition switch ªONº]Approximately 5V
224 R Mass air flow sensor[Engine is running]
+Warm-up condition
+Idle speed1.5 - 2.0V
313 L/WElectronic control fuel
injection pump[Engine is running]
+Warm-up condition
+Idle speedApproximately 0.1V
314 L/RElectronic control fuel
injection pump[Engine is running]
+Warm-up condition
+Idle speedApproximately 0.4V
316 PUElectronic control fuel
injection pump[Engine is running]
+Warm-up condition
+Idle speedApproximately 2.5V
317 PElectronic control fuel
injection pump[Engine is running]
+Warm-up condition
+Idle speedApproximately 2.5V
325 G ECM relay (Self-shutoff)[Ignition switch ªONº]
[Ignition switch ªOFFº]
+For a few seconds after turning ignition switch
ªOFFºApproximately 0.25V
[Ignition switch ªOFFº]
+A few seconds passed after turning ignition
switch ªOFFºBATTERY VOLTAGE
(11 - 14V)
331 ORCrankshaft position sen-
sor (TDC) ground[Engine is running]
+Warm-up condition
+Idle speedApproximately 0V
334 B/REngine coolant tempera-
ture sensor ground[Ignition switch ªONº]Approximately 0V
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
ECM Terminals and Reference Value (Cont'd)
EC-555