Page 275 of 1033

ACTIVE TEST MODE
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
COOLING FAN+Ignition switch: ON
+Operate the cooling fan at
ªLOWº, ªHIº speed and turn
ªOFFº using CONSULT-II.Cooling fan moves at ªLOWº, ªHIº
speed and stops.+Harness and connector
+Cooling fan motor
+Cooling fan relay
OFF ACCEL PO
SIG+Clears the self-learning fully closed accelerator position, detected by accelerator position sensor, from the
ECM.
GLOW RLY+Ignition switch: ON (Engine
stopped)
+Turn the glow relay ªONº and
ªOFFº using CONSULT-II and
listen to operating sound.Glow relay makes the operating
sound.+Harness and connector
+Glow relay
INJ TIMING*+Engine: Return to the original
trouble condition
+Retard the injection timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.+Electronic control fuel injection
pump
SWIRL CONT S/V1+Ignition switch: ON
+Turn solenoid valve ªONº and
ªOFFº with the CONSULT-II and
listen to operating sound.Solenoid valve makes an operating
sound.+Harness and connector
+Solenoid valve
EGR VOL CONT/V+Ignition switch: ON
+Change EGR volume control
valve opening step using CON-
SULT-II.EGR volume control valve makes
an operating sound.+Harness and connector
+EGR volume control valve
*: When using this item, DTC 0707 ªP7zF/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-1042
Page 278 of 1033

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 essen-
tial 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 inter-
mittently 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 performed. Follow the ªWork Flowº, EC-1047.
Before undertaking actual checks, take a few minutes to talk with
a customer who approaches with a driveability complaint. The
customer 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 electroni-
cally 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-1045
Page 280 of 1033
Work Flow
*1 Refer to MA section (ªChecking
and Replacing Fuel Filter and
Draining Waterº, ªENGINE MAIN-
TENANCEº).
*2 If time data of ªSELF-DIAG
RESULTSº is other than ª0º, per-
form ªTROUBLE DIAGNOSIS
FOR INTERMITTENT INCIDENTº,
EC-1076.*3 If the incident cannot be verified,
perform ªTROUBLE DIAGNOSIS
FOR INTERMITTENT INCIDENTº,
EC-1076.
*4 If the on board diagnostic system
cannot be performed, check main
power supply and ground circuit.Refer to ªTROUBLE DIAGNOSIS
FOR POWER SUPPLYº,
EC-1077.
*5 If malfunctioning part cannot be
detected, perform ªTROUBLE
DIAGNOSIS FOR INTERMIT-
TENT INCIDENTº, EC-1076.
SEF374YB
TROUBLE DIAGNOSIS Ð INTRODUCTIONZD30DDTi
EC-1047
Page 282 of 1033

Basic Inspection
Precaution:
Perform Basic Inspection without electrical or mechanical
loads applied;
+Shift lever is in neutral position,
+Heat up switch is OFF,
+Headlamp switch is OFF,
+Air conditioner switch is OFF,
+Rear defogger switch is OFF,
+Steering wheel is in the straight-ahead position, etc.
1 INSPECTION START
1. Check service records for any recent repairs that may indicate a related problem.
2. Check the current need for scheduled maintenance, especially for fuel filter and air cleaner filter. Refer to MA section.
3. Open engine hood and check the following:
+Harness connectors for improper connections
+Vacuum hoses for splits, kinks, or improper connections
+Wiring for improper connections, pinches, or cuts
SEF142I
4. Start engine and warm it up to the normal operating temperature.
cGO TO 2.
2 PREPARATION FOR CHECKING IDLE SPEED
With CONSULT-II
Connect CONSULT-II to the data link connector.
Without CONSULT-II
Install diesel tacho tester to the vehicle.
cGO TO 3.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONZD30DDTi
EC-1049
Page 283 of 1033
3 CHECK IDLE SPEED
With CONSULT-II
1. Select ªCKPSzRPM (TDC)º in ªDATA MONITORº mode with CONSULT-II.
2. Read idle speed.
SEF817Y
Without CONSULT-II
Check idle speed.
750 25 rpm
OK or NG
OKcINSPECTION END
NGcGO TO 4.
4 CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OKcGO TO 5.
NGcRepair or replace.
5 BLEED AIR FROM FUEL SYSTEM
1. Stop engine.
2. Using priming pump, bleed air from fuel system. Refer to ªAir Bleedingº, EC-1031.
cGO TO 6.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONZD30DDTi
Basic Inspection (Cont'd)
EC-1050
Page 284 of 1033
6 CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select ªCKPSzRPM (TDC)º in ªDATA MONITORº mode with CONSULT-II.
3. Read idle speed.
SEF817Y
Without CONSULT-II
1. Start engine and let it idle.
2. Check idle speed.
750 25 rpm
OK or NG
OKcINSPECTION END
NGcGO TO 7.
7 DRIN WATER FROM FUEL FILTER
Drain water from fuel filter. Refer to MA section (ªChecking and Replacing Fuel Filter and Draining Waterº, ªENGINE MAINTE-
NANCEº).
cGO TO 8.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONZD30DDTi
Basic Inspection (Cont'd)
EC-1051
Page 286 of 1033
9 CHECK AIR CLEANER FILTER
Check air cleaner filter for clogging or breaks.
OK or NG
OKcGO TO 10.
NGcReplace air cleaner filter.
10 CHECK FUEL INJECTION NOZZLE
Check fuel injection nozzle opening pressure. Refer to ªInjection pressure testº, EC-1025.
OK or NG
OKcGO TO 11.
NGcReplace fuel injection nozzle assembly.
11 CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select ªCKPSzRPM (TDC)º in ªDATA MONITORº mode with CONSULT-II.
3. Read idle speed.
SEF817Y
Without CONSULT-II
1. Start engine and let it idle.
2. Check idle speed.
750 25 rpm
OK or NG
OKcINSPECTION END
NGcGO TO 12.
12 CHECK COMPRESSION PRESSURE
Check compression pressure. Refer to EM section, ªMEASUREMENT OF COMPRESSION PRESSUREº.
OK or NG
OKcGO TO 13.
NGcFollow the instruction of ªMEASUREMENT OF COMPRESSION PRESSUREº.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONZD30DDTi
Basic Inspection (Cont'd)
EC-1053
Page 287 of 1033
13 CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select ªCKPSzRPM (TDC)º in ªDATA MONITORº mode with CONSULT-II.
3. Read idle speed.
SEF817Y
Without CONSULT-II
1. Start engine and let it idle.
2. Check idle speed.
750 25 rpm
OK or NG
OKcINSPECTION END
NGcReplace electronic control fuel injection pump.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONZD30DDTi
Basic Inspection (Cont'd)
EC-1054