Page 480 of 1306
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 lamp illuminates.
Can be detected by CONSULT-II?
Fuel cutBLACK SMOKE
WHITE SMOKEWarranty symptom code AG AH AJ AK AL AM AP HA
ENGINE CONTROL
Fuel cut system line*a, *c 1 1
EC-3615
*b 1 *2
Accelerator position sensor circuit *a, *b 1 1 EC-3516
Crankshaft position sensor (TDC) cir-
cuit*a, *b,
*d1 1 1 1 EC-3535
Charge air pressure sensor circuit*a, *c
1 EC-3601
*b 1
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 DESCRIPTIONYD25DDTi
Symptom Matrix Chart (Cont'd)
EC-3455
Page 482 of 1306

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 lamp illuminates.
Can be detected by CONSULT-II?
Fuel cutBLACK SMOKE
WHITE SMOKEWarranty symptom code AG AH AJ AK AL AM AP HA
ENGINE CONTROL
Start signal circuit *a, *b EC-3631 *3
PNP switch circuit*a, *b
1 1 EC-3634
*c
Accelerator position switch (Idle) cir-
cuit*a, *c
EC-3516
*b 1 1 *4
Accelerator position switch (Full) cir-
cuit*a, *b 1 1 EC-3516
Ignition switch circuit*a
EC-3471
*b*5
Power supply for ECM circuit*a
111
EC-3471
*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 DESCRIPTIONYD25DDTi
Symptom Matrix Chart (Cont'd)
EC-3457
Page 484 of 1306

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 lamp illuminates.
Can be detected by CONSULT-II?
Fuel cutBLACK SMOKE
WHITE SMOKEWarranty symptom code AG AH AJ AK AL AM AP HA
ENGINE CONTROL
EGR volume control valve circuit*a, *b
EC-3606
*c 1 *8
Glow relay circuit*a 1
EC-3622*9
*b*10
ECM relay (Self-shutoff) circuit*a 111
EC-3471
*b*11
ECM, Connector circuit *a, *b222222222222EC-3502,
3582, 3599
Air conditioner relay circuit*a
EC-3645*12
*b*13
Air conditioner switch circuit*a, *c
EC-3645*13
*b*14
1 - 5: The numbers refer to the order of inspection.
*a: Open
*b: Short
*c: Ground short
*d: Noise
*8: Does not stop operating.
*9: Glow lamp does not turn on.
*10: Glow lamp does not turn off.
*11: Ground short makes engine unable to stop.
*12: Air conditioner does not operate.
*13: Air conditioner does not stop operating.
*14: Air conditioner does not work.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD25DDTi
Symptom Matrix Chart (Cont'd)
EC-3459
Page 490 of 1306

TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA (DC Voltage and Pulse
Signal)
15 G/W Air conditioner relayEngine 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
16 L/W Glow lampIgnition switch ªONº
Glow lamp is ªONºApproximately 1V
Ignition switch ªONº
Glow lamp is ªOFFºBATTERY VOLTAGE
(11 - 14V)
17 G/Y Stop lamp switchIgnition switch ªONº
Brake pedal fully releasedApproximately 0V
Ignition switch ªONº
Brake pedal depressedBATTERY VOLTAGE
(11 - 14V)
18 W/GMalfunction indicator
lampIgnition switch ªONº
Approximately 1V
Engine is running.
Idle speedBATTERY VOLTAGE
(11 - 14V)
19 L/OREngine coolant tempera-
ture sensorEngine is running.
Approximately 0 - 4.8V
Output voltage varies with
engine coolant temperature
20 R Start signalIgnition switch ªONº
Approximately 0V
Ignition switch ªSTARTº
BATTERY VOLTAGE
(11 - 14V)
21 Y Air conditioner switchEngine 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 0V
22 G/ORPark/Neutral position
switchIgnition switch ªONº
Gear position is ªNeutralºApproximately 0V
Ignition switch ªONº
Except the above gear positionBATTERY VOLTAGE
(11 - 14V)
23 WAccelerator position sen-
sorIgnition switch ªONº
Accelerator pedal fully released0.29 - 0.79V
Ignition switch ªONº
Accelerator pedal fully depressed3.48 - 4.64V
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONYD25DDTi
ECM Terminals and Reference Value
(Cont'd)
EC-3465
Page 505 of 1306

Description
The engine coolant temperature sensor is used to detect the
engine coolant temperature. The sensor modifies a voltage sig-
nal from the ECM. The modified signal returns to the ECM as the
engine coolant temperature input. The sensor uses a thermistor
which is sensitive to the change in temperature. The electrical
resistance of the thermistor decreases as temperature
increases.
Engine coolant tempera-
ture ÉC (ÉF)Voltage* (V) Resistance (kW)
þ10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.3 0.68 - 1.0
90 (194) 1.0 0.236 - 0.260
*: These data are reference values and measured between ECM terminal 19
(Engine coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/
output voltage. Doing so may damage the ECM's transistor.
Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis Logic
Malfunction is detected when ... Check Items (Possible Cause)
+An excessively high or low voltage from the sensor is entered
to ECM.+Harness or connectors (The sensor circuit is open or shorted.)
+Engine coolant temperature sensor
DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 5 seconds.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-3483.
WITHOUT CONSULT-II
1) Turn ignition switch ªONº and wait at least 5 seconds.
2) Turn ignition switch ªOFFº, wait at least 5 seconds and then
turn ªONº.
3) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º
with ECM.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-3483.
SEF594K
SEF012P
SEF817Y
DTC 0103 COOLANT TEMP SENYD25DDTi
EC-3480
Page 506 of 1306
Wiring Diagram
GEC274A
DTC 0103 COOLANT TEMP SENYD25DDTi
EC-3481
Page 507 of 1306
Diagnostic Procedure
1 CHECK ECTS POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor harness connector.
SEC230D
3. Turn ignition switch ªONº.
4. Check voltage between ECTS terminal 2 and ground with CONSULT-II or tester.
SEF401Y
OK or NG
OKcGO TO 3.
NGcGO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E237, M279 (LHD models)
+Harness connectors E237, F36 (RHD models)
+Harness for open or short between engine control temperature sensor and ECM
cRepair open circuit or short to ground or short to power in harness or connectors.
3 CHECK ECTS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between ECTS terminal 1 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OKcGO TO 5.
NGcGO TO 4.
DTC 0103 COOLANT TEMP SENYD25DDTi
EC-3482
Page 508 of 1306
4 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E237, M279 (LHD models)
+Harness connectors E237, F36 (RHD models)
+Harness for open or short between engine coolant temperature sensor and ECM
cRepair open circuit or short to ground or short to power in harness or connectors.
5 CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Remove engine coolant temperature sensor from the engine.
2. Check resistance between ECTS terminals 1 and 2 as shown in the figure.
SEF304X
OK or NG
OKcGO TO 6.
NGcReplace engine coolant temperature sensor.
6 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-3469.
cINSPECTION END
DTC 0103 COOLANT TEMP SENYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3483