Page 345 of 1033

6 CHECK COOLING FAN GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect cooling fan motor-1 harness connector.
SEF691V
3. Check harness continuity between cooling fan relay-1 terminal 3 and cooling fan motor-1 terminals 1, 3, cooling fan motor-1 ter-
minals 2, 4 and body ground. Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OKcGO TO 7.
NGcRepair open circuit or short to ground or short to power in harness or connectors.
7 CHECK COOLING FAN OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 14 and cooling fan relay-1 terminal 1. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OKcGO TO 9.
NGcGO TO 8.
8 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E127, M21
+Harness connectors M52, F7
+Harness for open or short between cooling fan relay-1 and ECM
cRepair open circuit or short to ground or short to power in harness or connectors.
DTC 0208 OVER HEATZD30DDTi
Diagnostic Procedure (Cont'd)
EC-1112
Page 346 of 1033
9 CHECK COOLING FAN RELAY-1
Check continuity between cooling fan relay-1 terminals 3 and 5 under the following conditions.
SEF608X
OK or NG
OKcGO TO 10.
NGcReplace cooling fan relay.
10 CHECK COOLING FAN MOTOR-1
Supply battery voltage between the following terminals and check operation.
SEF292Z
OK or NG
OKcGO TO 11.
NGcReplace cooling fan motor.
11 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-1076.
cINSPECTION END
DTC 0208 OVER HEATZD30DDTi
Diagnostic Procedure (Cont'd)
EC-1113
Page 347 of 1033
12 CHECK COOLING SYSTEM FOR LEAK
Apply pressure to the cooling system with a tester, and check if the pressure drops.
Testing pressure: 157 kPa (1.57 bar, 1.6 kg/cm
2, 23 psi)
CAUTION:
Higher than the specified pressure may cause radiator damage.
SLC754A
Pressure should not drop.
OK or NG
OKcGO TO 14.
NGcGO TO 13.
13 DETECT MALFUNCTIONING PART
Check the following for leak.
+Hose
+Radiator
+Water pump (Refer to LC section, ªWater Pumpº.)
cRepair or replace.
14 CHECK RADIATOR CAP
Apply pressure to cap with a tester and check radiator cap relief pressure.
SLC755A
Radiator cap relief pressure:
79 - 98 kPa (0.78 - 0.98 bar, 0.8 - 1.0 kg/cm2, 11 - 14 psi)
OK or NG
OKcGO TO 15.
NGcReplace radiator cap.
DTC 0208 OVER HEATZD30DDTi
Diagnostic Procedure (Cont'd)
EC-1114
Page 348 of 1033
15 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
OKcGO TO 16.
NGcReplace thermostat.
16 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
OKcGO TO 17.
NGcReplace engine coolant temperature sensor.
DTC 0208 OVER HEATZD30DDTi
Diagnostic Procedure (Cont'd)
EC-1115
Page 349 of 1033

17 CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to ªMAIN 12 CAUSES OF OVERHEATINGº, EC-1116.
cINSPECTION END
Main 12 Causes of Overheating
Engine Step Inspection item Equipment Standard Reference page
OFF 1+Blocked radiator
+Blocked condenser
+Blocked radiator grille
+Blocked bumper+Visual No blocking Ð
2+Coolant mixture+Coolant tester 30 - 50% coolant mixture See ªRECOMMENDED
FLUIDS AND LUBRI-
CANTSº in MA section.
3+Coolant level+Visual Coolant up to MAX level
in reservoir tank and
radiator filler neckSee ªChanging Engine
Coolantº, ªENGINE MAIN-
TENANCEº in MA sec-
tion.
4+Radiator cap+Pressure 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 5+Coolant leaks+Visual No leaks See ªSystem Checkº,
ªENGINE COOLING SYS-
TEMº in LC section.
ON*2 6+Thermostat+Touch the upper and
lower radiator hosesBoth hoses should be hot. See ªThermostatº and
ªRadiatorº, ªENGINE
COOLING SYSTEMº in
LC section.
ON*1 7+Cooling fan+Visual Operating See ªDTC 0208 OVER
HEATº, EC-1105.
OFF 8+Combustion gas leak+Color checker chemical
tester 4 gas analyzerNegative Ð
ON*3 9+Coolant temperature
gauge+Visual Gauge less than 3/4
when drivingÐ
+Coolant overflow to res-
ervoir tank+Visual No overflow during driving
and idlingSee ªChanging Engine
Coolantº, ªENGINE MAIN-
TENANCEº in MA sec-
tion.
OFF*4 10+Coolant return from res-
ervoir tank to radiator+Visual Should be initial level in
reservoir tankSee ªENGINE MAINTE-
NANCEº in MA section.
OFF 11+Cylinder head+Straight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)See ªInspectionº, ªCYLIN-
DER HEADº in EM sec-
tion.
12+Cylinder block and pis-
tons+Visual 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-1116
Page 350 of 1033
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)
+ECM calculation function is malfunctioning.+ECM
(ECCS-D control module)
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-1118.
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-1118.
SEC220B
SEF817Y
DTC 0301 ECM 2, DTC 0901 ECM 12ZD30DDTi
EC-1117
Page 351 of 1033
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-1117, 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-1117, again.
4. Perform ªDiagnostic Test Mode II (Self-diagnostic results)º.
5. Is the DTC 0301 or 0901 displayed again?
Yes or No
YescReplace ECM.
NocINSPECTION END
DTC 0301 ECM 2, DTC 0901 ECM 12ZD30DDTi
EC-1118
Page 352 of 1033

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 tim-
ing 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
information 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
injection 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 tempera-
ture.
CAM RING POSITION SENSOR
The sensor detects the passing of the protrusion on the sensor
wheel in the injection pump by the semiconductor magnetic
resistance element sensor. The cam ring position sensor syn-
chronizes 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 P9zFUEL TEMP SENZD30DDTi
EC-1119