TROUBLE DIAGNOSIS
EC-1409
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TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEBS0036Z
INTRODUCTION
The engine has an ECM to control major systems such as fuel injec-
tion control, fuel injection timing control, glow control system, etc.
The ECM accepts input signals from sensors and instantly actuators.
It is essential that both input and output signals are proper and sta-
ble. At the same time, it is important that there are no malfunctions
such as vacuum leaks, or other malfunctions with the engine.
It is much more difficult to diagnose a malfunction that occurs inter-
mittently rather than continuously. Most intermittent malfunctions are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only may not find the cause of the incidents. A road
test with CONSULT-II or a circuit tester connected should be per-
formed. Follow the EC-1410, "
WORK FLOW" .
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 incidents, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “Diagnostic Worksheet” like the exam-
ple on next page should be used.
Start your diagnosis by looking for “conventional” incidents first. This
will help troubleshoot driveability incidents on an electronically con-
trolled engine vehicle.
MEF036D
SEF233G
SEF234G
TROUBLE DIAGNOSIS
EC-1411
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Description for Work Flow
DIAGNOSTIC WORK SHEET
There are many operating conditions that lead to the malfunction of
engine components. A good grasp of such conditions can make trou-
bleshooting faster and more accurate.
In general, each customer feels differently about an incident. It is
important to fully understand the symptoms or conditions for a cus-
tomer complaint.
Utilize a diagnostic worksheet like the one shown below in order to
organize all the information for troubleshooting.
STEP DESCRIPTION
STEP IGet detailed information about the conditions and the environment when the incident/symptom occurred using the
EC-1411, "
DIAGNOSTIC WORK SHEET" .
STEP IIBefore confirming the concern, check and write down (print out using CONSULT-II) the DTC, then erase the DTC.
Refer to EC-1406
.
If the incident cannot be verified, perform EC-1441, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
Study the relationship between the cause, specified by DTC, and the symptom described by the customer. (The
“Symptom Matrix Chart” will be useful. Refer to EC-1416
.) Also check related service bulletins for information.
STEP IIITry to confirm the symptom and under what conditions the incident occurs.
The “DIAGNOSTIC WORK SHEET” is useful to verify the incident. Connect CONSULT-II to the vehicle in DATA
MONITOR (AUTO TRIG) mode and check real time diagnosis results.
If the incident cannot be verified, perform EC-1441, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
If the malfunction code is detected, skip STEP IV and perform STEP V.
STEP IVTry to detect the DTC by driving in (or performing) the “DTC Confirmation Procedure”. Check and read the DTC by
using CONSULT-II.
During the DTC verification, be sure to connect CONSULT-II to the vehicle in DATA MONITOR (AUTO TRIG) mode
and check real time diagnosis results.
If the incident cannot be verified, perform EC-1441, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
In case the “DTC Confirmation Procedure” is not available, perform the “Overall Function Check” instead. The DTC
cannot be displayed by this check, however, this simplified “check” is an effective alternative.
The “NG” result of the “Overall Function Check” is the same as the DTC detection.
STEP VTake the appropriate action based on the results of STEP I through IV.
If the malfunction code is indicated, proceed to Trouble Diagnosis for DTC PXXXX.
If the normal code is indicated, proceed to the Basic Inspection, EC-1412
. Then perform inspections according to the
Symptom Matrix Chart. Refer to EC-1416
.
STEP VIIdentify where to begin diagnosis based on the relationship study between symptom and possible causes. Inspect the
system for mechanical binding, loose connectors or wiring damage using (tracing) “Harness Layouts”.
Gently shake the related connectors, components or wiring harness with CONSULT-II set in “DATA MONITOR (AUTO
TRIG)” mode.
Check the voltage of the related ECM terminals or monitor the output data from the related sensors with CONSULT-II.
Refer to EC-1425
or EC-1437 .
The “Diagnostic Procedure” in EC section contains a description based on open circuit inspection. A short circuit
inspection is also required for the circuit check in the Diagnostic Procedure. For details, refer to GI-23, "
How to Per-
form Efficient Diagnosis for an Electrical Incident" , “Circuit Inspection”.
Repair or replace the malfunction parts.
If the malfunctioning part cannot be detected, perform EC-1441, "
TROUBLE DIAGNOSIS FOR INTERMITTENT
INCIDENT" .
STEP VIIOnce you have repaired the circuit or replaced a component, you need to run the engine in the same conditions and
circumstances which resulted in the customer's initial complaint.
Perform the “DTC Confirmation Procedure” and confirm the normal code (DTC P0000) is detected. If the incident is
still detected in the final check, perform STEP VI by using a different method from the previous one.
Before returning the vehicle to the customer, be sure to erase the unnecessary (already fixed) DTC in ECM. (Refer to
EC-1406
.)
SEF907L
TROUBLE DIAGNOSIS
EC-1413
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1.INSPECTION START
1. Check service records for any recent repairs that may indicate a related incident.
2. Check the current need for scheduled maintenance, especially for fuel filter and air cleaner filter. Refer to
MA-7, "
PERIODIC MAINTENANCE" .
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
4. Start engine and warm it up to the normal operating tempera-
ture.
>> GO TO 2.
2.PREPARATION FOR CHECKING IDLE SPEED
With CONSULT-II
Connect CONSULT-II to the data link connector.
>> GO TO 3.
3.CHECK IDLE SPEED
With CONSULT-II
1. Select “CKPS·RPM (TDC)” in “DATA MONITOR” mode with CONSULT-II.
2. Read idle speed.
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4.CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace.
SEF142I
725±25 rpm
SEF817Y
EC-1414
[YD]
TROUBLE DIAGNOSIS
5. BLEED AIR FROM FUEL SYSTEM
1. Stop engine.
2. Use priming pump to bleed air from fuel system. Refer to EC-1404, "
AIR BLEEDING" .
>> GO TO 6.
6. CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select “CKPS·RPM (TDC)” in “DATA MONITOR” mode with CONSULT-II.
3. Read idle speed.
OK or NG
OK >>INSPECTION END
NG >> GO TO 7.
7. DRAIN WATER FROM FUEL FILTER
Drain water from fuel filter. Refer to EC-1404, "
WATER DRAINING" .
>> GO TO 8.
8. CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select “CKPS·RPM (TDC)” in “DATA MONITOR” mode with CONSULT-II.
3. Read idle speed.
OK or NG
OK >>INSPECTION END
NG >> GO TO 9.
9. CHECK AIR CLEANER FILTER
Check air cleaner filter for clogging or breaks.
OK or NG
OK >> GO TO 10.
NG >> Replace air cleaner filter.725±25 rpm
SEF817Y
725±25 rpm
SEF817Y
TROUBLE DIAGNOSIS
EC-1415
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10.CHECK BATTERY VOLTAGE
Check battery voltage.
OK or NG
OK >> GO TO 12.
NG >> GO TO 11.
11 . CHECK BATTERY
Refer to SC-3, "
BATTERY" .
OK or NG
OK >> Check charging system. Refer to SC-12 .
NG >> Repair or replace.
12.CHECK COMPRESSION PRESSURE
Check compression pressure. Refer to EM-182, "
CHECKING COMPRESSION PRESSURE" .
OK or NG
OK >> GO TO 11.
NG >> Follow the instruction of “CHECKING COMPRESSION PRESSURE”.
13.CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select “CKPS·RPM (TDC)” in “DATA MONITOR” mode with CONSULT-II.
3. Read idle speed.
OK or NG
OK >>INSPECTION END
NG >> 1. Replace fuel injector.
2. GO TO 3. Voltage: More than 12.13V
725±25 rpm
SEF817Y
TROUBLE DIAGNOSIS
EC-1427
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ECA24 BMass air flow sensor
ground[Engine is running]●Warm-up condition
●Idle speedApproximately 0V
A25 G/W Injector's ground[Engine is running]
●Warm-up condition
●Idle speedApproximately 0V
A26 LG/RAccelerator pedal position
sensor 2 ground[Ignition switch “ON”]Approximately 0V
A27 W Sensor's power supply[Ignition switch “ON”]Approximately 5V
A28 PU/RAccelerator pedal position
sensor 1 power supply [Ignition switch “ON”]Approximately 5V
A29 W/PU EDU injector check signal[Engine is running]
●Warm-up condition
●Idle speed1 - 5V
[Engine is running]
●Warm-up condition
●Engine speed is 2,000 rpm1 - 5V
A31 W/L Power supply for ECM[Ignition switch “ON”]BATTERY VOLTAGE
(11 - 14V)
B3
B4
B5
B6W
OR/B
W/L
GYEGR volume control valve[Engine is running]
●Warm-up condition
●Idle speed0.1 - 14V
(Voltage signals of each ECM ter-
minals differ according to the con-
trol position of EGR volume
control valve.)
B9 G/BFuel injector adjustment
resistor No.2
[Ignition switch “ON”]0.2 - 4.8V
(There are individual differences
between fuel injector adjustment
resistors.) B10 Y/BFuel injector adjustment
resistor No.4
B11 R/BFuel injector adjustment
resistor No.3
B12 W/BFuel injector adjustment
resistor No.1
B13
B14Y/R
Y/RCommon rail fuel pressure
sensor[Engine is running]
●Warm-up condition
●Idle speed1.6 - 1.8V
[Engine is running]
●Warm-up condition
●Engine speed is 2,000 rpm1.8 - 2.0V TERMI-
NAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse Signal)
PBIB0391E
PBIB0392E
EC-1436
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TROUBLE DIAGNOSIS
ACTIVE TEST MODE
REAL TIME DIAGNOSIS IN DATA MONITOR MODE
CONSULT-II has two kinds of triggers and they can be selected by touching “SETTING” in “DATA MONITOR”
mode.
1. “AUTO TRIG” (Automatic trigger):
–The malfunction will be identified on the CONSULT-II screen in
real time.
In other words, DTC will be displayed if the malfunction is
detected by ECM.
At the moment a malfunction is detected by ECM, “MONITOR”
in “DATA MONITOR” screen is changed to “Recording Data ...
xx%” as shown in the figure, and the data after the malfunction
detection is recorded. Then when the percentage reached
100%, “REAL-TIME DIAG” screen is displayed. If “STOP” is
touched on the screen during “ Recording Data ... xx%”, “REAL-
TIME DIAG” screen is also displayed.
The recording time after the malfunction detection and the recording speed can be changed by “TRIG-
GER POINT” and “Recording Speed”. Refer to CONSULT-II OPERATION MANUAL.
2. “MANU TRIG” (Manual trigger):
–DTC will not be displayed automatically on CONSULT-II screen
even though a malfunction is detected by ECM.
DATA MONITOR can be performed continuously even though a
malfunction is detected.
Use these triggers as follows:
1. “AUTO TRIG”
–While trying to detect the DTC by performing the “DTC Confir-
mation Procedure”, be sure to select to “DATA MONITOR
(AUTO TRIG)” mode. You can confirm the malfunction at the
moment it is detected.
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
POWER BAL-
ANCE
●Engine: After warming up, idle the
engine.
●A/C switch “OFF”
●Shift lever “N”
●Cut off each injector signal one at
a time using CONSULT-IIEngine runs rough or dies.
●Harness and connectors
●Compression
●Fuel injectors
COOLING FAN
●Ignition switch: ON
●Operate the cooling fan at “LOW”,
“HI” speed and turn “OFF” using
CONSULT-II.Cooling fan moves at “LOW”, “HI”
speed and stops.●Harness and connector
●Cooling fan motor
●Cooling fan relay
OFF ACCEL PO
SIG
●This mode is used for ECM to learn accelerator pedal released positions.
GLOW RELAY
●Ignition switch: ON (Engine
stopped)
●Turn the glow relay “ON” and
“OFF” using CONSULT-II and lis-
ten to operating sound.Glow relay makes the operating
sound.●Harness and connector
●Glow relay
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
PRES REGULA-
TOR
●Ignition switch: ON
●Change fuel pressure in common
rail using CONSULT-IIFuel leaks.●Fuel line
●Fuel pressure relief valve
PBIB0480E
SEF707X
EC-1444
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POWER SUPPLY CIRCUIT FOR ECM
Diagnostic Procedure
EBS0036B
1. INSPECTION START
Start engine.
Is engine running?
Ye s o r N o
Yes >> GO TO 6.
No >> GO TO 2.
2. CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch “ON”.
2. Check voltage between ECM terminals D18, D19 and ground
with CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. DETECT MALFUNCTIONING PART
Check the following.
●Harness connectors M63, F30
●Fuse block (J/B) connector M1
●10A fuse
●Harness for open or short between ECM and fuse
>> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals A5, A6, A7 and engine ground. Refer to Wiring Dia-
gram.
4. Also check harness for short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to power in harness or connectors. Voltage: Battery voltage
PBIB0356E
Continuity should exist.