Page 405 of 1767

ACTIVE TEST MODE
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
COOLING FANIIgnition switch: ON
IOperate the cooling fan at
ªLOWº, ªHIº speed and turn
ªOFFº using CONSULT-II.Cooling fan moves at ªLOWº, ªHIº
speed and stops.IHarness and connector
ICooling fan motor
ICooling fan relay
OFF ACCEL PO
SIGIClears the self-learning fully closed accelerator position, detected by accelerator position sensor, from the
ECM.
GLOW RLYIIgnition switch: ON (Engine
stopped)
ITurn the glow relay ªONº and
ªOFFº using CONSULT-II and
listen to operating sound.Glow relay makes the operating
sound.IHarness and connector
IGlow relay
INJ TIMING*IEngine: Return to the original
trouble condition
IRetard the injection timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IElectronic control fuel injection
pump
SWIRL CONT S/V1IIgnition switch: ON
ITurn solenoid valve ªONº and
ªOFFº with the CONSULT-II and
listen to operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
EGR VOL CONT/VIIgnition switch: ON
IChange EGR volume control
valve opening step using CON-
SULT-II.EGR volume control valve makes
an operating sound.IHarness and connector
IEGR volume control valve
*: When using this item, DTC 0707 ªP7×F/INJ TIMG FBº may be detected. If so, erase it because it is not a malfunction.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONZD30DDTi
CONSULT-II (Cont'd)
EC-43
Page 408 of 1767

Introduction
The engine has an ECM to control major systems such as fuel
injection control, fuel injection timing control, glow control system,
etc. The ECM accepts input signals from sensors and instantly
drives electronic control fuel injection pump. It is essential that both
input and output signals are proper and stable. At the same time,
it is important that there are no problems such as vacuum leaks,
or other problems with the engine.
It is much more difficult to diagnose a problem that occurs intermit-
tently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this
case, careful checking of suspected circuits may help prevent the
replacement of good parts.
A visual check only may not find the cause of the problems. A road
test with CONSULT-II or a circuit tester connected should be per-
formed. Follow the ªWork Flowº, EC-48.
Before undertaking actual checks, take a few minutes to talk with
a customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such problems, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A ªDiagnostic Worksheetº like the
example on next page should be used.
Start your diagnosis by looking for ªconventionalº problems first.
This will help troubleshoot driveability problems on an electronically
controlled engine vehicle.
DIAGNOSTIC WORKSHEET
There are many operating conditions that lead to the malfunction
of engine components. A good grasp of such conditions can make
troubleshooting faster and more accurate.
In general, each customer feels differently about a problem. It is
important to fully understand the symptoms or conditions for a
customer complaint.
Utilize a diagnostic worksheet like the one shown below in order to
organize all the information for troubleshooting.
SEF858S
SEF233G
SEF234G
SEF907L
TROUBLE DIAGNOSIS Ð INTRODUCTIONZD30DDTi
EC-46
Page 417 of 1767
13 CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select ªCKPS×RPM (TDC)º in ªDATA MONITORº mode with CONSULT-II.
3. Read idle speed.
SEF817Y750 25 rpm
Without CONSULT-II
1. Start engine and let it idle.
2. Check idle speed.
750 25 rpm
OK or NG
OKEINSPECTION END
NGEReplace electronic control fuel injection pump.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONZD30DDTi
Basic Inspection (Cont'd)
EC-55
Page 418 of 1767

Symptom Matrix Chart
SYSTEM Ð Basic engine control sys-
temSYMPTOM
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
Electronic control fuel injection pump
mainframe4444444445534 Ð *1
Injection nozzle33333333344 3EC-24 *2
Glow system1111EC-239
Engine body3333333 344 3 EMsection *3
EGR system3 3 EC-222
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 DESCRIPTIONZD30DDTi
EC-56
Page 419 of 1767

SYSTEM Ð Basic engine control sys-
temSYMPTOM
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
Electronic control fuel injection pump
mainframe443 4 54 333 Ð *1
Injection nozzle 3 3 4 EC-24 *2
Glow system 1 EC-239
Engine body 3 3 3 3 3 3 EM section *3
EGR system 3 EC-222
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 DESCRIPTIONZD30DDTi
Symptom Matrix Chart (Cont'd)
EC-57
Page 420 of 1767
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-88
*b
Engine coolant temperature sensor
circuit*a, *b 1 1 1 1 EC-95 *1
Vehicle speed sensor circuit *a, *b 1 EC-99
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 DESCRIPTIONZD30DDTi
Symptom Matrix Chart (Cont'd)
EC-58
Page 421 of 1767
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
Electronic control fuel injection pump
circuit*a, *b 1
111
Ð
*c, *d 1
Mass air flow sensor circuit*a, *c
1 EC-88
*b 1
Engine coolant temperature sensor
circuit*a, *b 1 1 1 1 EC-95 *1
Vehicle speed sensor circuit *a, *b 1 EC-99
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 DESCRIPTIONZD30DDTi
Symptom Matrix Chart (Cont'd)
EC-59
Page 435 of 1767

TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA (DC Voltage and Pulse
Signal)
26 Y/B Vehicle speed sensorEngine is running.
Lift up the vehicle
In 1st gear position
Vehicle speed is 10 km/h (6 MPH)0 - Approximately 4.8V
SEF257Z
Engine is running.
Lift up the vehicle
In 2nd gear position
Vehicle speed is 30 km/h (19 MPH)Approximately 2.2V
SEF258Z
29 LG/R Accelerator switch (F/C)Ignition switch ªONºAccelerator pedal fully releasedBATTERY VOLTAGE
(11 - 14V)
Ignition switch ªONº
Accelerator pedal depressedApproximately 0V
30 LG/Y A/T signal No. 3Engine is running.
Warm-up condition
Idle speedApproximately 0V
Engine is running.
Warm-up condition
Engine speed is 2,000 rpmApproximately 7.7V
31 L/YAccelerator position
switch (Idle)Ignition switch ªONº
Accelerator pedal fully releasedBATTERY VOLTAGE
(11 - 14V)
Ignition switch ªONº
Accelerator pedal depressedApproximately 0V
32 R/LAccelerator position
switch (Full)Ignition switch ªONº
Accelerator pedal releasedApproximately 0V
Ignition switch ªONº
Accelerator pedal fully depressedBATTERY VOLTAGE
(11 - 14V)
33 GElectronic control fuel
injection pumpEngine is running.
Warm-up condition
Idle speedApproximately 2.5V
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONZD30DDTi
ECM Terminals and Reference Value (Cont'd)
EC-73