TROUBLE DIAGNOSIS
EC-1089
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TROUBLE DIAGNOSIS
Trouble Diagnosis Introduction INFOID:0000000004499937
INTRODUCTION The engine has an ECM to control major systems such as fuel con-
trol, ignition control, idle air control system, etc. The ECM accepts
input signals from sensors and instantly drives actuators. 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 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 driv ability complaint. The customer
can supply good information about such incidents, especially inter-
mittent ones. Find out what symptoms are present and under what
conditions they occur. A Diagnosti c Worksheet like the example on
"Worksheet Sample" should be used.
Start your diagnosis by looking for conventional malfunctions first.
This will help troubleshoot drivability malfunctions on an electroni-
cally controlled engine vehicle.
WORK FLOW MEF036D
SEF233G
SEF234G
EC-1100< SERVICE INFOMATION >
[MR TYPE 2]
TROUBLE DIAGNOSIS
Engine Control Comp onent Parts Location INFOID:0000000004499941
1. Ignition coil (with power transistor) and spark plug 2. Intake valve timing control solenoid
valve 3. Refrigerant pressure sensor
4. Knock sensor 5. Fuel injector 6. Cooling fan motor
7. Camshaft position sensor (PHASE) 8. IPDM E/R 9. ECM
10. Mass air flow sensor (with intake air temperature sensor) 11. Engine coolant temperature sensor 12. Electric throttle control actuator
(with built-in throttle position sensor,
throttle control motor)
13. EVAP canister purge volume control solenoid valve PBIB3261E
EC-1102< SERVICE INFOMATION >
[MR TYPE 2]
TROUBLE DIAGNOSIS
: Vehicle front
1. Intake valve timing control solenoid valve 2. Knock sensor 3. IPDM E/R
4. Fuel pump fuse (15A) 5. Fuel level sensor unit and fuel pump harness connector (view with in-
spection hole cover removed) 6. Fuel level sensor unit and fuel pump
7. Fuel pressure regulator 8. Fuel level sensor 9. Fuel tank temperature sensor
10. Ignition coil (with power transistor) and spark plug 11. Fuel injector BBIA0725E
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NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item AT OD CANCEL
[ON/OFF] • Indicates [ON/OFF] condition of A/T O/D cancel signal sent
from the TCM. • For M/T models always “OFF” is displayed
CRUISE LAMP
[ON/OFF] • Indicates [ON/OFF]
condition of CRUISE lamp determined
by the ECM according to the input signals.
SET LAMP
[ON/OFF] • Indicates [ON/OFF] condition of SET lamp determined by the
ECM according to the input signals.
A/F ADJ-B1 • Indicates the correction factor stored in ECM. The factor is
calculated from the difference between the target air/fuel ratio
stored in ECM and the air/fuel ratio calculated from air fuel ra-
tio (A/F) sensor 1 signal.
Monitored item [Unit] Description Remarks TEST ITEM CONDITION JUDGMENT 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
• Shift lever: P or N (A/T, CVT), Neutral (M/T)
• 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 “LOW”, “HI” and “OFF” with CONSULT-III. Cooling fan moves and stops. • Harness and connectors
• Cooling fan relay
• Cooling fan motor
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
FUEL PUMP RE-
LAY • Ignition switch: ON
(Engine stopped)
• Turn the fuel pump relay ON and OFF using CONSULT-III and lis-
ten 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
• EVAP canister purge volume con- trol solenoid valve
FUEL/T TEMP
SEN • Change the fuel tank temperature using CONSULT-III.
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DTC P0300 - P0304 MULTIPLE CYLINDER
MISFIRE, NO. 1 - 4 CYLINDER
MISFIRE
On Board Diagnosis Logic INFOID:0000000004500140
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank-
shaft position (CKP) sensor (POS) signal to vary , ECM can determine that a misfire is occurring.
The misfire detection logic consists of the following two conditions.
1. One Trip Detection Logic (Three Way Catalyst Damage) On the 1st trip, when a misfire condition occurs that can damage the three way catalyst (TWC) due to
overheating, the MIL will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor (POS) signal every 200 engine revo-
lutions for a change.
When the misfire condition decreases to a level t hat will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level t hat will not damage the TWC, the MIL will remain on.
If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.
2. Two Trip Detection Logic (Exhaust quality deterioration) For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MIL will only
light when the misfire is detected on a second trip. Du ring this condition, the ECM monitors the CKP sen-
sor signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.
DTC Confirmation Procedure INFOID:0000000004500141
CAUTION:
Always drive vehicle in safe manner according to traf fic conditions and obey all traffic laws when driv-
ing.
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Restart engine and let it idle for about 15 minutes.
4. Check 1st trip DTC.
5. If 1st trip DTC is detected, go to EC-1284, " Diagnosis Procedure " .
NOTE:
If 1st trip DTC is not detected during above proc edure, performing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditi ons to (1st trip) Freeze Frame Data for a certain
time. Refer to table below. Sensor Input Signal to ECM ECM function
Crankshaft position sensor (POS) Engine speed On board diagnosis of misfire DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0300
0300 Multiple cylinder misfire
detected Multiple cylinder misfire.
• Improper spark plug
• Insufficient compression
• Incorrect fuel pressure
• Fuel injector circuit is open or shorted
• Fuel injector
• Intake air leak
• The ignition signal circuit is open or shorted
• Lack of fuel
• Drive plate or flywheel
• Air fuel ratio (A/F) sensor 1
• Incorrect PCV hose connection
P0301
0301 No.1 cylinder misfire de-
tected No. 1 cylinder misfires.
P0302
0302 No. 2 cylinder misfire
detected No. 2 cylinder misfires.
P0303
0303 No. 3 cylinder misfire
detected No. 3 cylinder misfires.
P0304
0304 No. 4 cylinder misfire
detected No. 4 cylinder misfires.
DTC P0300 - P0304 MULTIPLE CYLINDER
MISFIRE, NO. 1 - 4 CYLINDER MIS-
FIRE
EC-1285
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Yes >> GO TO 4.
No >> GO TO 9. 4.
CHECK FUEL INJECTOR
Does each fuel injector make an operating sound at idle?
Yes or No Yes >> GO TO 5.
No >> Check fuel injector(s) and circuit(s). Refer to EC-1508 .
5.
CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Do the following procedure in the place where ventilation is good without the combustible.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse (1) in IPDM E/R (2) to release fuel pres- sure.
NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
- : Vehicle front
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel
pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electri-
cal discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal
portion as shown in the figure.
11. Crank engine for about 3 seconds, and check whether spark is generated between the spark plug and the grounded metal por-
tion.
CAUTION:
• Do not approach to the spar k plug and the ignition coil
within 50cm. Be careful not to get an electrical shock
while checking, because the el ectrical discharge voltage
becomes 20kV or more.
• It might cause to damage the igni tion coil if the gap of more than 17 mm (0.66 in) is taken.
NOTE:
When the gap is less than 13 mm (0.52 in), the sp ark might be generated even if the coil is mal-
functioning.
OK or NG OK >> GO TO 9.
NG >> GO TO 6. 6.
CHECK FUNCTION OF IGNITION COIL-II
1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a known-good spark plug. PBIB3332E
Spark should be generated. PBIB2958E
PBIB2325E
EC-1286< SERVICE INFOMATION >
[MR TYPE 2]
DTC P0300 - P0304 MULTIPLE CYLINDER
MISFIRE, NO. 1 - 4 CYLINDER MIS-
FIRE
3. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.
OK or NG OK >> GO TO 7.
NG >> Check ignition coil, power transistor and their circuits. Refer to EC-1518 .
7.
CHECK SPARK PLUG
Check the initial spark plug for fouling, etc.
OK or NG OK >> Replace spark plug(s) with standard type one(s). For
spark plug type, refer to EM-227, " Standard and Limit " .
NG >> 1. Repair or clean spark plug. 2. GO TO 8. 8.
CHECK FUNCTION OF IGNITION COIL-III
1. Reconnect the initial spark plugs.
2. Crank engine for about three seconds, and recheck whether spark is generated between the spark plug
and the grounded portion.
OK or NG OK >>
INSPECTION END
NG >> Replace spark plug(s) with standard type one(s). For spark plug type, refer to EM-227, " Standard
and Limit " .
9.
CHECK COMPRESSION PRESSURE
Check compression pressure. Refer to EM-185, " On-Vehicle Service " .
OK or NG OK >> GO TO 10.
NG >> Check pistons, piston rings, valves, valve seats and cylinder head gaskets. 10.
CHECK FUEL PRESSURE
1. Install all removed parts.
2. Release fuel pressure to zero. Refer to EC-1086, " Fuel Pressure Check " .
3. Install fuel pressure gauge and check fuel pressure. Refer to EC-1086, " Fuel Pressure Check " .
OK or NG OK >> GO TO 12.
NG >> GO TO 11. 11.
DETECT MALFUNCTIONING PART
Check the following.
• Fuel pump and circuit (Refer to EC-1513 .)
• Fuel pressure regulator (Refer to EC-1086, " Fuel Pressure Check " .)
• Fuel lines (Refer to FL-4, " Checking Fuel Line " .)
• Fuel filter for clogging
>> Repair or replace.
Spark should be generated.
SEF156I
Spark should be generated.
At idling: Approximately 350 kPa (3.57 kg/cm 2
, 51 psi)
DTC P0420 THREE WAY CATALYST FUNCTION
EC-1305
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DTC P0420 THREE WAY CATALYST FUNCTION
On Board Diagnosis Logic INFOID:0000000004500166
The ECM monitors the switching frequency ratio of air fuel ratio (A/F)
sensor 1 and heated oxygen sensor 2.
A three way catalyst (manifold) with high oxygen storage capacity
will indicate a low switching frequency of heated oxygen sensor 2.
As oxygen storage capacity decr eases, the heated oxygen sensor 2
switching frequency will increase.
When the frequency ratio of air fuel ratio (A/F) sensor 1 and heated
oxygen sensor 2 approaches a specified limit value, the three way
catalyst (manifold) malfunction is diagnosed.
DTC Confirmation Procedure INFOID:0000000004500167
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
TESTING CONDITION:
Do not hold engine speed for more than the specified minutes below.
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
2. Start engine and warm it up to the normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. Make sure that “COOLAN TEMP/S” indicates more than 70 °C (158 °F).
If not, warm up engine and go to next step when “COOLAN TEMP/S” indication reaches to 70°C (158 °F).
7. Open engine hood.
8. Select “DTC & SRT CONFIRMATION” then “SRT WORK SUPPORT” mode with CONSULT-III.
9. Rev engine up to 2,000 to 3,000 rpm and hold it for 3 consecutive minutes then release the accelerator pedal completely.
If “INCMP” of “CATALYST” changed to “CMPLT”, go to step 12.
10. Wait 5 seconds at idle.
11. Rev engine up to 2,000 to 3,000 rpm and maintain it unt il “INCMP” of “CATALYST” changes to “CMPLT” (It
will take approximately 5 minutes).
If not “CMPLT”, stop engine and cool it down to less than 70 °C (158 °F) and then retest from step 1.
12. Check 1st trip DTC. If 1st trip DTC is detected, go to EC-1306, " Diagnosis Procedure " .
Overall Function Check INFOID:0000000004500168
Use this procedure to check the overall function of the th ree way catalyst (manifold). During this check, a 1st
trip DTC might not be confirmed. SEF484YB
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0420
0420 Catalyst system efficiency
below threshold • Three way catalyst (manifold) does not operate
properly.
• Three way catalyst (manifold) does not have enough oxygen storage capacity. • Three way catalyst (manifold)
• Exhaust tube
• Intake air leaks
• Fuel injector
• Fuel injector leaks
• Spark plug
• Improper ignition timing