TROUBLE DIAGNOSISEC-89
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TROUBLE DIAGNOSIS
Trouble Diagnosis IntroductionINFOID:0000000001325927
INTRODUCTION
The engine has an ECM to control major systems such as fuel con-
trol, ignition control, idle air c
ontrol system, etc. The ECM accepts
input signals from sensors and instantly drives actuators. It is essen-
tial that both input and output si gnals are proper and stable. At the
same time, it is important that there are no malfunctions such as vac-
uum leaks, fouled spark plugs, or other malfunctions with the engine.
It is much more difficult to diagnose an incident that occurs intermit-
tently rather than continuously. Most intermittent incidents 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 t he cause of the incidents. A road
test with CONSULT-III (or GST) or a circuit tester connected should
be performed. Follow the WORK FLOW on “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
example on “DIAGNOSTIC WORKSHEET” should be used.
Start your diagnosis by looking for conventional malfunctions first.
This will help troubleshoot driveability malfunctions on an electroni-
cally controlled engine vehicle.
WORK FLOW
MEF036D
SEF233G
SEF234G
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EC-124
< SERVICE INFORMATION >[VQ35DE]
TROUBLE DIAGNOSIS
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item
VHCL SPD CUTNON/
CUT Indicates the vehicle cruise condition.
NON: Vehicle speed is maintained at the ASCD set
speed.
CUT: Vehicle speed increased to excessively high
compared with the ASCD set speed, and ASCD op-
eration is cut off.
LO SPEED CUT NON/
CUT Indicates the vehicle cruise condition.
NON: Vehicle speed is maintained at the ASCD set
speed.
CUT: Vehicle speed decreased to excessively low
compared with the ASCD set speed, and ASCD op-
eration is cut off.
AT OD MONITOR ON/OFF Indicates [ON/OFF] condition of A/T O/D according
to the input signal from the TCM.
AT OD CANCEL ON/OFF Indicates [ON/OFF] condition of A/T O/D cancel
signal sent from the TCM.
DIST SW ON/OFF Indicates [ON/OFF] condition from DISTANCE
switch signal.
CRUISE LAMP ON/OFF Indicates [ON/OFF] condition of CRUISE lamp de-
termined by the ECM according to the input signals.
SET LAMP ON/OFF Indicates [ON/OFF] condition of SET lamp deter-
mined by the ECM according to the input signals.
A/F ADJ-B1 — Indicates the correction of factor stored in ECM. The factor is calculated from the difference be-
tween the target air-fuel ratio stored in ECM and the
air-fuel ratio calculated from A/F sensor 1 signal.
A/F ADJ-B2
w
Monitored item Unit Description Remarks
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJEC-
TION Engine: Return to the original
trouble condition
Change the amount of fuel injec- tion using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Fuel injector
Air fuel ratio (A/F) sensor 1
IGNITION TIM-
ING Engine: Return to the original
trouble condition
Timing light: Set
Retard the ignition timing using
CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
Perform Idle Air Volume Learning.
POWER BAL-
ANCE Engine: After warming up, idle the
engine.
A/C switch: OFF
Selector lever: P or N
Cut off each fuel injector signal one at a time using CONSULT-III. Engine runs rough or dies.
Harness and connectors
Compression
Fuel injector
Power transistor
Spark plug
Ignition coil
COOLING FAN* Ignition switch: ON
Turn the cooling fan “HI”, “MID”,
“LOW” and “OFF” using CON-
SULT-III. Cooling fan moves and stops.
Harness and connectors
Cooling fan motor
IPDM E/R
ENG COOLANT
TEMP Engine: Return to the original
trouble condition
Change the engine coolant tem-
perature using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM. Harness and connectors
Engine coolant temperature sen-
sor
Fuel injector
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TROUBLE DIAGNOSISEC-125
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*: Leaving cooling fan OFF with CONSULT-III while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For details, refer to
EC-55, "Emission-Related Diagnostic Information".
SRT WORK SUPPORT Mode
This mode enables a technician to drive a vehicle to set the SRT while monitoring the SRT status.
DTC WORK SUPPORT Mode
*: DTC P1442 and P1456 does not apply to S50 models but appears in DTC Work Support Mode screens.
Generic Scan Tool (GST) FunctionINFOID:0000000001325937
DESCRIPTION
FUEL PUMP RE-
LAY Ignition switch: ON
(Engine stopped)
Turn the fuel pump relay “ON” and “OFF” using CONSULT-III
and listen to operating sound. Fuel pump relay makes the operat-
ing sound.
Harness and connectors
Fuel pump relay
PURG VOL
CONT/V Engine: After warming up, run en-
gine at 1,500 rpm.
Change the EVAP canister purge volume control solenoid valve
opening percent using CON-
SULT-III. Engine speed changes according to
the opening percent.
Harness and connectors
Solenoid valve
FUEL/T TEMP
SEN Change the fuel tank temperature using CONSULT-III.
VENT CON-
TROL/V Ignition switch: ON
(Engine stopped)
Turn solenoid valve “ON” and “OFF” with the CONSULT-III and
listen to operating sound. Solenoid valve makes an operating
sound.
Harness and connectors
Solenoid valve
V/T ASSIGN AN-
GLE Engine: Return to the original
trouble condition
Change intake valve timing using
CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Intake valve timing control sole-
noid valve
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
Test mode Test item Corresponding DTC No. Reference page
EVAPORATIVE SYS-
TEM PURG FLOW P0441 P0441
EC-336
EVP SML LEAK P0442/P1442* P0442EC-341
EVP V/S LEAK P0456/P1456* P0456EC-394
PURG VOL CN/V P1444 P0443EC-348
A/F SEN1A/F SEN1 (B1) P1276 P0130
EC-212A/F SEN1 (B1) P1278/1279 P0133EC-236
A/F SEN1 (B2) P1286 P0150EC-212
A/F SEN1 (B2) P1288/1289 P0153EC-236
HO2S2HO2S2 (B1) P0139 P0139
EC-265
HO2S2 (B1) P1146 P0138EC-254
HO2S2 (B1) P1147 P0137EC-245
HO2S2 (B2) P0159 P0159EC-265
HO2S2 (B2) P1166 P0158EC-254
HO2S2 (B2) P1167 P0157EC-245
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TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-133
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DETAILED PROCEDURE
1.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Confirm that the testing conditions are met. Refer to EC-131, "
Testing Condition".
3. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
NOTE:
PBIB3214E
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EC-134
< SERVICE INFORMATION >[VQ35DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximat
ely 1 minute because they may fluctuate. It is NG
if the indication is out of the SP value even a little.
OK or NG
OK >> GO TO 17.
NG (Less than the SP value)>>GO TO 2.
NG (More than the SP value)>>GO TO 3.
2.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 4.
NG (More than the SP value)>>GO TO 19.
3.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 6.
NG (More than the SP value)>>GO TO 6.
NG (Less than the SP value)>>GO TO 25.
4.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Stop the engine.
2. Disconnect PCV hose, and then plug it.
3. Start engine.
4. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> GO TO 5.
NG >> GO TO 6.
5.CHANGE ENGINE OIL
1. Stop the engine.
2. Change engine oil. NOTE:
This symptom may occur when a large amount of gasoline is mixed with engine oil because of driving
conditions (such as when engine oil temperature does not rise enough since a journey distance is too
short during winter). The symptom will not be detec ted after changing engine oil or changing driving con-
dition.
>>INSPECTION END
6.CHECK FUEL PRESSURE
Check fuel pressure. (Refer to EC-87, "
Fuel Pressure Check".)
OK or NG
OK >> GO TO 9.
NG (Fuel pressure is too high)>>Replace fuel pressure regulator, refer to EC-87, "
Fuel Pressure Check". GO
TO 8.
NG (Fuel pressure is too low)>>GO TO 7.
7.DETECT MALFUNCTIONING PART
1. Check the following.
- Clogged and bent fuel hose and fuel tube
- Clogged fuel filter
- Fuel pump and its circuit (Refer to EC-558
.)
2. If NG, repair or replace the malfunctioning part. (Refer to EC-87, "
Fuel Pressure Check".)
If OK, replace fuel pressure regulator.
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TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-135
< SERVICE INFORMATION > [VQ35DE]
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>> GO TO 8.
8.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 9.
9.PERFORM POWER BALANCE TEST
1. Perform “POWER BALANCE ” in “ACTIVE TEST” mode.
2. Make sure that the each cylinder produces a momentary engine speed drop.
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10.DETECT MALFUNCTIONING PART
1. Check the following.
- Ignition coil and its circuit (Refer to EC-569
.)
- Fuel injector and its circuit (Refer to EC-552
.)
- Intake air leakage
- Low compression pressure (Refer to EM-100, "
On-Vehicle Service".)
2. If NG, repair or replace the malfunctioning part.
If OK, replace fuel injector. (It may be caus ed by leakage from fuel injector or clogging.)
>> GO TO 11.
11 .CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 12.
12.CHECK A/F SENSOR 1 FUNCTION
Perform all DTC Confirmation Proc edure related with A/F sensor 1.
For DTC P0130, P0150, refer to EC-212, "
DTC Confirmation Procedure".
For DTC P0131, P0151, refer to EC-220, "
DTC Confirmation Procedure".
For DTC P0132, P0152, refer to EC-228, "
DTC Confirmation Procedure".
For DTC P0133, P0153, refer to EC-236, "
DTC Confirmation Procedure".
For DTC P2A00, P2A03, refer to EC-532, "
DTC Confirmation Procedure".
OK or NG
OK >> GO TO 15.
NG >> GO TO 13.
13.CHECK A/F SENSOR 1 CIRCUIT
Perform Diagnostic Procedure according to corresponding DTC.
>> GO TO 14.
14.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
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EC-136
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TROUBLE DIAGNOSIS - SPECIFICATION VALUE
OK >>
INSPECTION END
NG >> GO TO 15.
15.DISCONNECT AND RECONNE CT ECM HARNESS CONNECTOR
1. Stop the engine.
2. Disconnect ECM harness connector. Check pin terminal and connector for damage, and then reconnect it.
>> GO TO 16.
16.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> Detect malfunctioning part according to EC-96, "
Symptom Matrix Chart".
17.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> INSPECTION END
NG (More than the SP value)>>GO TO 18.
NG (Less than the SP value)>>GO TO 25.
18.DETECT MALFUNCTIONING PART
1. Check for the cause of large engine friction. Refer to the following.
- Engine oil level is too high
- Engine oil viscosity
- Belt tension of power steering, alternat or, A/C compressor, etc. is excessive
- Noise from engine
- Noise from transmission, etc.
2. Check for the cause of insufficient combustion. Refer to the following.
- Valve clearance malfunction
- Intake valve timing control function malfunction
- Camshaft sprocket installation malfunction, etc.
>> Repair or replace malfunctioning part, and then GO TO 30.
19.CHECK INTAKE SYSTEM
Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
Crushed air ducts
Malfunctioning seal of air cleaner element
Uneven dirt of air cleaner element
Improper specification of intake air system
OK or NG
OK >> GO TO 21.
NG >> Repair or replace malfunctioning part, and then GO TO 20.
20.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”
Select “A/F ALPHA-B1”, “A/F ALPHA-B2”, and “B/F UEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and
make sure that the each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG (“B/FUEL SCHDL” is more, “A/F ALPHA-B1”, “A/F ALPHA-B2” are less than the SP value)>>GO TO 21.
21.DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR
1. Stop the engine.
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TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-137
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2. Disconnect mass air flow sensor harness connecto
r. Check pin terminal and connector for damage and
then reconnect it again.
>> GO TO 22.
22.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> 1. Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to EC-182
.
2. GO TO 29.
NG >> GO TO 23.
23.CHECK “MAS A/F SE-B1”
Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 24.
NG (More than the SP value)>>Replace ma ss air flow sensor, and then GO TO 29.
24.REPLACE ECM
1. Replace ECM.
2. Perform initialization of IVIS(NATS) system and registration of all IVIS(NATS) ignition key IDs.
Refer to BL-187, "
ECM Re-Communicating Function".
3. Perform EC-84, "
VIN Registration".
4. Perform EC-85, "
Accelerator Pedal Released Position Learning".
5. Perform EC-85, "
Throttle Valve Closed Position Learning".
6. Perform EC-85, "
Idle Air Volume Learning".
>> GO TO 29.
25.CHECK INTAKE SYSTEM
Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
Crushed air ducts
Malfunctioning seal of air cleaner element
Uneven dirt of air cleaner element
Improper specification of intake air system
OK or NG
OK >> GO TO 27.
NG >> Repair or replace malfunctioning part, and then GO TO 26.
26.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” m ode, and make sure that the indication is within the
SP value.
OK or NG
OK >> INSPECTION END
NG (Less than the SP value)>>GO TO 27.
27.CHECK “MAS A/F SE-B1”
Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 28.
NG (Less than the SP value)>>Replace ma ss air flow sensor, and then GO TO 30.
28.CHECK INTAKE SYSTEM
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