Page 803 of 2493

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
Page 824 of 2493

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
Page 838 of 2493

SYSTEM Ð Basic engine control
systemSYMPTOM
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
Electronic control fuel injection
pump mainframe44345433Ð*1
Injection nozzle 3 3 3 4 3 EC-509 *2
Glow system 1 1 EC-677
Engine body 3 3 3 3 3 3 EM section *3
EGR system 3 EC-686
Air cleaner and ducts 3 3 MA section *4
1 - 5: The numbers refer to the order of inspection.
(continued on next page)
*1: Fuel injection system malfunction or fuel injection timing control system malfunction may be the cause.
*2: Depends on open-valve pressure and spray pattern.
*3: Caused mainly by insufficient compression pressure.
*4: Symptom varies depending on off-position of air duct, etc.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-542
Page 839 of 2493
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
Page 840 of 2493
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
Page 842 of 2493
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
Page 844 of 2493
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
Page 846 of 2493

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
EGR volume control valve circuit*a, *b
EC-686
*c 1 *6
Glow relay circuit*a 1
EC-677*7
*b*8
ECM relay (Self-shutoff) circuit*a
EC-666
*b*9
ECM, Connector circuit *a, *b22222222222EC-664,
604
Air conditioner relay circuit*a
EC-700*10
*b*11
Air conditioner switch circuit*a, *c
EC-700*11
*b*12
1 - 5: The numbers refer to the order of inspection.
*a: Open
*b: Short
*c: Ground short
*d: Noise
*6: Does not stop operating.
*7: Glow lamp does not turn on.
*8: Glow lamp does not turn off.
*9: Ground short makes engine unable to stop.
*10: Air conditioner does not operate.
*11: Air conditioner does not stop operating.
*12: Air conditioner does not work.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD
Symptom Matrix Chart (Cont'd)
EC-550