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
Page 482 of 1767

18 CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to ªMAIN 12 CAUSES OF OVERHEATINGº, EC-120.
EINSPECTION END
Main 12 Causes of Overheating
Engine Step Inspection item Equipment Standard Reference page
OFF 1IBlocked radiator
IBlocked condenser
IBlocked radiator grille
IBlocked bumperIVisual No blocking Ð
2ICoolant mixtureICoolant tester 30 - 50% coolant mixture See ªRECOMMENDED
FLUIDS AND LUBRI-
CANTSº in MA section.
3ICoolant levelIVisual Coolant up to MAX level
in reservoir tank and
radiator filler neckSee ªChanging Engine
Coolantº, ªENGINE MAIN-
TENANCEº in MA section.
4IRadiator capIPressure tester 78 - 98 kPa
(0.78 - 0.98 bar, 0.8 - 1.0
kg/cm
2, 11 - 14 psi)
59 - 98 kPa (0.59 - 0.98
bar, 0.6 - 1.0 kg/cm
2,
9 - 14 psi) (Limit)See ªSystem Checkº,
ªENGINE COOLING SYS-
TEMº in LC section.
ON*2 5ICoolant leaksIVisual No leaks See ªSystem Checkº,
ªENGINE COOLING SYS-
TEMº in LC section.
ON*2 6IThermostatITouch the upper and
lower radiator hosesBoth hoses should be hot. See ªThermostatº and
ªRadiatorº, ªENGINE
COOLING SYSTEMº in
LC section.
ON*1 7ICooling fanIVisual Operating See ªDTC 0208 OVER
HEATº, EC-109.
OFF 8ICombustion gas leakIColor checker chemical
tester 4 gas analyzerNegative Ð
ON*3 9ICoolant temperature
gaugeIVisual Gauge less than 3/4
when drivingÐ
ICoolant overflow to res-
ervoir tankIVisual No overflow during driving
and idlingSee ªChanging Engine
Coolantº, ªENGINE MAIN-
TENANCEº in MA section.
OFF*4 10ICoolant return from res-
ervoir tank to radiatorIVisual Should be initial level in
reservoir tankSee ªENGINE MAINTE-
NANCEº in MA section.
OFF 11ICylinder headIStraight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)See ªInspectionº, ªCYLIN-
DER HEADº in EM sec-
tion.
12ICylinder block and pis-
tonsIVisual No scuffing on cylinder
walls or pistonSee ªInspectionº, ªCYLIN-
DER BLOCKº in EM sec-
tion.
*1: Engine running at idle.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to ªOVERHEATING CAUSE ANALYSISº in LC section.
DTC 0208 OVER HEATZD30DDTi
Diagnostic Procedure (Cont'd)
EC-120
Page 483 of 1767
Description
The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The unit controls the engine.
On Board Diagnosis Logic
Malfunction is detected when ... Check Items (Possible Cause)
IECM calculation function is malfunctioning.IECM
DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait at least 2 seconds.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-122.
WITHOUT CONSULT-II
1) Turn ignition switch ªONº and wait at least 2 seconds.
2) Start engine and wait at least 2 seconds.
3) Turn ignition switch ªOFFº, wait at least 5 seconds and then turn
ªONº.
4) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º with
ECM.
5) If DTC is detected, go to ªDiagnostic Procedureº, EC-122.
SEC220B
SEF817Y
DTC 0301 ECM 2, DTC 0901 ECM 12ZD30DDTi
EC-121
Page 484 of 1767
Diagnostic Procedure
1 INSPECTION START
With CONSULT-II
1. Turn ignition switch ªONº.
2. Select ªSELF DIAG RESULTSº mode with CONSULT-II.
3. Touch ªERASEº.
4. Perform ªDTC Confirmation Procedureº, EC-121, again.
5. Is the malfunction displayed again?
Without CONSULT-II
1. Turn ignition switch ªONº.
2. Erase the Diagnostic Test Mode II (Self-diagnostic results) memory.
3. Perform ªDTC Confirmation Procedureº, EC-121, again.
4. Perform ªDiagnostic Test Mode II (Self-diagnostic results)º.
5. Is the DTC 0301 or 0901 displayed again?
YesorNo
Ye sEReplace ECM.
NoEINSPECTION END
DTC 0301 ECM 2, DTC 0901 ECM 12ZD30DDTi
EC-122
Page 485 of 1767

Description
SYSTEM DESCRIPTION
The ECM and the electronic control fuel injection pump control unit
(abbreviated as the injection pump control unit) perform the real
time communication (signal exchange).
The ECM transmits the signals of the target fuel injection amount,
target fuel injection timing, and engine speed, etc., and receives the
signals of the pump speed and fuel temperature, etc. from the
injection pump control unit.
By those signals, the injection pump controls the optimum fuel
injection amount and injection timing of the spill valve and timing
control valve.
Injection pump control unit has an on board diagnostic system,
which detects malfunctions related to sensors or actuators built-into
electronic control fuel injection pump. These malfunction informa-
tion are transferred through the line (circuit) from injection pump
control unit to ECM.
FUEL INJECTION AMOUNT CONTROL
In accordance with the target fuel injection amount signal from the
ECM, the injection amount is controlled by controlling the spill valve
in the injection pump and by changing the needle opening time.
FUEL INJECTION TIMING CONTROL
Based on the target fuel injection timing signal from the ECM, the
injection timing is controlled in accordance with the timer spring by
performing the duty control of the timing control valve in the injec-
tion pump and by adjusting the pressure of the timer piston high
pressure chamber.
FUEL TEMPERATURE SENSOR
The sensor detects the fuel temperature in the injection pump and
calibrates the injection amount change by the fuel temperature.
CAM RING POSITION SENSOR
The sensor detects the passing of the protrusion on the sensor
wheel in the injection pump by the semiconductor magnetic resis-
tance element sensor. The cam ring position sensor synchronizes
with the cam ring, and detects the actual advance amount. The
injection pump control unit measures the injection pump revolution
by the signal of the cam ring position sensor.
SEF437Y
DTC 0402 P9×FUEL TEMP SENZD30DDTi
EC-123
Page 486 of 1767

CONSULT-II Reference Value in Data Monitor
Mode
Remarks: Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
FUEL TEMP SENIEngine: After warming up More than 40ÉC (104ÉF)
SPILL/VIEngine: After warming up Approx. 13ÉCA
INJ TIMG C/VIEngine: After warming up,
idle the engine.Approx. 50 - 70%
DECELER F/CUTIEngine: After warm-
ing upIdle OFF
BARO SENIIgnition switch: ONAltitude
Approx.0m(0ft): Approx. 100.62 kPa (1.0062 bar, 1.026 kg/cm
2, 14.59
psi)
Approx. 1,000 m (3,281 ft): Approx. 88.95 kPa (0.8895 bar, 0.907 kg/cm
2,
12.90 psi)
Approx. 1,500 m (4,992 ft): Approx. 83.16 kPa (0.8316 bar, 0.848 kg/cm
2,
12.06 psi)
Approx. 2,000 m (6,562 ft): Approx. 78.36 kPa (0.7836 bar, 0.799 kg/cm
2,
11.36 psi)
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)
33 GElectronic control fuel
injection pumpEngine is running.
Warm-up condition
Idle speedApproximately 2.5V
40 RElectronic control fuel
injection pumpEngine is running.
Warm-up condition
Idle speedApproximately 2.5V
52 YElectronic control fuel
injection pumpEngine is running.
Idle speedApproximately 0.1V
53 ORElectronic control fuel
injection pumpEngine is running.
Idle speedApproximately 0.35V
On Board Diagnosis Logic
Malfunction is detected when .... Check Items (Possible cause)
IAn improper voltage signal from fuel temperature sensor
(Built-into electronic control fuel injection pump) is sent to
injection pump control unit.IHarness or connectors
(Electronic control fuel injection pump circuit is open or
shorted.)
IElectronic control fuel injection pump
DTC 0402 P9×FUEL TEMP SENZD30DDTi
EC-124
Page 487 of 1767
DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch ªONº and wait at least 2 seconds.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and run it for at least 2 seconds at idle speed.
(If engine does not run, turn ignition switch to ªSTARTº for at
least 2 seconds.)
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-128.
WITHOUT CONSULT-II
1) Turn ignition switch ªONº and wait at least 2 seconds.
2) Start engine and run it for at least 2 seconds at idle speed.
(If engine does not run, turn ignition switch to ªSTARTº for at
least 2 seconds.)
3) Turn ignition switch ªOFFº, wait at least 5 seconds and then turn
ªONº.
4) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º with
ECM.
5) If DTC is detected, go to ªDiagnostic Procedureº, EC-128.SEF817Y
DTC 0402 P9×FUEL TEMP SENZD30DDTi
EC-125
Page 488 of 1767
Wiring Diagram
LHD MODELS
YEC181A
DTC 0402 P9×FUEL TEMP SENZD30DDTi
EC-126