Page 457 of 1767

Description
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine cool-
ant temperature input. The sensor uses a thermistor which is sen-
sitive 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 - 1.00
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)
IAn excessively high or low voltage from the sensor is entered
to ECM.IHarness or connectors (The sensor circuit is open or shorted.)
IEngine 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-97.
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-97.
SEF594K
SEF012P
SEF817Y
DTC 0103 COOLANT TEMP SENZD30DDTi
EC-95
Page 459 of 1767
Diagnostic Procedure
1 CHECK ECTS POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor harness connector.
MEC022E
3. Turn ignition switch ªONº.
4. Check voltage between ECTS terminal 2 and ground with CONSULT-II or tester.
SEF401Y
OK or NG
OKEGO TO 3.
NGEGO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E225, F108
IHarness connectors F135, M842 (RHD models)
IHarness for open or short between engine control temperature sensor and ECM
ERepair 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
OKEGO TO 5.
NGEGO TO 4.
DTC 0103 COOLANT TEMP SENZD30DDTi
EC-97
Page 460 of 1767
4 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E225, F108
IHarness connectors F135, M842 (RHD models)
IHarness for open or short between engine coolant temperature sensor and ECM
ERepair 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
OKEGO TO 6.
NGEReplace engine coolant temperature sensor.
6 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-78.
EINSPECTION END
DTC 0103 COOLANT TEMP SENZD30DDTi
Diagnostic Procedure (Cont'd)
EC-98
Page 471 of 1767
Description
SYSTEM DESCRIPTION
Sensor Input signal to ECM ECM function Actuator
Vehicle speed sensor Vehicle speed
Cooling fan con-
trolCooling fan relay Engine coolant temperature sensor Engine coolant temperature
Air conditioner switch Air conditioner ªONº signal
The ECM controls the cooling fan corresponding to the vehicle speed, engine coolant temperature, air condi-
tioner ON signal. The control system has 2-step control [ON/OFF].
OPERATION
CONSULT-II Reference Value in Data Monitor
Mode
Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
AIR COND SIGIEngine: After warming up, idle the
engineAir conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates.)ON
COOLING FANIWhen cooling fan is stopped. OFF
IWhen cooling fan operates. ON
SEF450Z
DTC 0208 OVER HEATZD30DDTi
EC-109
Page 472 of 1767

ECM Terminals and Reference Value
Specification data are reference values and are measured between each terminal 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.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
14 LG/R Cooling fan relayEngine is running.
Cooling fan is not operatingBATTERY VOLTAGE
(11 - 14V)
Engine is running.
Cooling fan is operatingApproximately 0.1V
On Board Diagnosis Logic
This diagnosis continuously monitors the engine coolant temperature.
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
Malfunction is detected when ... Check Items (Possible Cause)
ICooling fan does not operate properly (Overheat).
ICooling fan system does not operate properly (Overheat).
IEngine coolant was not added to the system using the proper
filling method.IHarness or connectors
(The cooling fan circuit is open or shorted.)
ICooling fan
IRadiator hose
IRadiator
IRadiator cap
IWater pump
IThermostat
IFan belt
IEngine coolant temperature sensor
For more information, refer to ªMAIN 12 CAUSES OF
OVERHEATINGº, EC-120.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant following the procedure in the MA
section (ªChanging Engine Coolantº, ªENGINE MAINTENANCEº). Also, replace the engine oil.
1) Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure to
use coolant with the proper mixture ratio. Refer to MA section (ªAnti-freeze Coolant Mixture Ratioº,
ªRECOMMENDED LUBRICANTS AND FLUIDSº).
2) After refilling coolant, run engine to ensure that no water-flow noise is emitted.
DTC 0208 OVER HEATZD30DDTi
EC-110
Page 473 of 1767

Overall Function Check
Use this procedure to check the overall function of the cooling fan.
During this check, a DTC might not be confirmed.
WARNING:
Never remove the radiator cap when the engine is hot. Serious
burns could be caused by high pressure fluid escaping from
the radiator.
Wrap a thick cloth around the cap. Carefully remove the cap
by turning it a quarter turn to allow built-up pressure to
escape. Then turn the cap all the way off.
WITH CONSULT-II
1) Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-114.
2) Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-114.
3) Turn ignition switch ªONº.
4) Perform ªCOOLING FANº in ªACTIVE TESTº mode with CON-
SULT-II and make sure that cooling fans operate when touch-
ing ªHIGHº or ªLOWº.
If NG, go to ªDiagnostic Procedureº, EC-114.
WITHOUT CONSULT-II
1) Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-114.
2) Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-114.
3) Disconnect engine coolant temperature sensor harness con-
nector.
4) Connect 150Wresistor to engine coolant temperature sensor
harness connector.
5) Start engine and make sure that cooling fan operates.
Be careful not to overheat engine.
6) If NG, go to ªDiagnostic Procedureº, EC-114.
AEC640
SEF111X
MEC475B
DTC 0208 OVER HEATZD30DDTi
EC-111
Page 476 of 1767
Diagnostic Procedure
1 INSPECTION START
Do you have CONSULT-II?
YesorNo
Ye sEGO TO 2.
NoEGO TO 3.
2 CHECK COOLING FAN OPERATION
With CONSULT-II
1. Turn ignition switch ªONº.
2. Perform ªCOOLING FANº in ªACTIVE TESTº mode with CONSULT-II.
SEF646X
3. Make sure that cooling fan operates.
OK or NG
OKEGO TO 12.
NGEGO TO 4.
3 CHECK COOLING FAN OPERATION
Without CONSULT-II
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor harness connector.
3. Connect 150Wresistor to engine coolant temperature sensor harness connector.
4. Restart engine and make sure that cooling fan operates.
MEC475B
OK or NG
OKEGO TO 12.
NGEGO TO 4.
DTC 0208 OVER HEATZD30DDTi
EC-114
Page 481 of 1767
16 CHECK THERMOSTAT
1. Remove thermostat.
2. Check valve seating condition at normal room temperatures.
It should seat tightly.
3. Check valve opening temperature and valve lift.
SLC343
Valve opening temperature:
82ÉC (180ÉF) [standard] (Models for cold areas)
76.5ÉC (170ÉF) [standard] (Models for except cold areas)
Valve lift:
More than 10 mm/95ÉC (0.394 in/203ÉF)
4. Check if valve is closed at 5ÉC (9ÉF) below valve opening temperature. For details, refer to LC section, ªThermostatº.
OK or NG
OKEGO TO 17.
NGEReplace thermostat.
17 CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Remove engine coolant temperature sensor.
2. Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in the figure.
SEF304X
OK or NG
OKEGO TO 18.
NGEReplace engine coolant temperature sensor.
DTC 0208 OVER HEATZD30DDTi
Diagnostic Procedure (Cont'd)
EC-119