P0301

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE





On Board Diagnosis Logic
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crankshaft 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 signal every 200 engine revolutions for a change.
When the misfire condition decreases to a level that 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 that 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. During this condition, the ECM monitors the CKP sensor signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.









DTC Confirmation Procedure

CAUTION:
Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws when driving.

NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
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 P0300.

NOTE:
If 1st trip DTC is not detected during above procedure, 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 conditions to (1st trip) Freeze Frame Data for a certain time. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following conditions should be satisfied at the same time.





The time to driving varies according to the engine speed in the freeze frame data.









Diagnosis Procedure
1.CHECK FOR INTAKE AIR LEAK AND PCV HOSE
1. Start engine and run it at idle speed.
2. Listen for the sound of the intake air leak.
3. Check PCV hose connection.
OK or NG
OK - GO TO 2.
NG - Discover air leak location and repair.
2.CHECK FOR EXHAUST SYSTEM CLOGGING
Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.
OK or NG
OK - GO TO 3.
NG - Repair or replace it.
3.PERFORM POWER BALANCE TEST
With CONSULT-III
1. Perform "POWER BALANCE" in "ACTIVE TEST" mode.
2. Is there any cylinder which does not produce a momentary engine speed drop?
Without CONSULT-III
When disconnecting each fuel injector harness connector one at a time, is there any cylinder which does not produce a momentary engine speed drop?





Yes or No
Yes - GO TO 4.
No - GO TO 7.
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 Diagnosis Procedure.
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 in IPDM E/R to release fuel pressure.

NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pressure applies again during the following procedure.
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 electrical 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 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 portion.

Spark should be generated.

CAUTION:





- Do not approach to the spark plug and the ignition coil within 50cm. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20kV or more.
- It might cause to damage the ignition coil if the gap of more than 17 mm is taken.

NOTE:
When the gap is less than 13 mm, the spark might be generated even if the coil is malfunctioning.
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.
3. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.

Spark should be generated.

OK or NG
OK - GO TO 7.
NG - Check ignition coil, power transistor and their circuits. Refer to Diagnosis Procedure .
7.CHECK SPARK PLUG





Check the initial spark plug for fouling, etc.
OK or NG
OK - Replace malfunctioning spark plug(s) with standard type one(s). For spark plug type, refer to Removal and Installation.
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 3 seconds, and recheck whether spark is generated between the spark plug and the grounded portion.

Spark should be generated.

OK or NG
OK >> INSPECTION END
NG - Replace malfunctioning spark plug(s) with standard type one(s). For spark plug type, refer to Removal and Installation.
9.CHECK COMPRESSION PRESSURE
Check compression pressure. Refer to Testing and Inspection.
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 Testing and Inspection.
3. Install fuel pressure gauge and check fuel pressure. Refer to Testing and Inspection.

At idling: Approximately 350 kPa (3.57 kg/cm2, 51 psi)

3. Install fuel pressure gauge and check fuel pressure. Refer to Testing and Inspection.
OK or NG
OK - GO TO 12.
NG - GO TO 11.
11.DETECT MALFUNCTIONING PART
Check the following.
- Fuel pump and circuit (Refer to Diagnosis Procedure.)
- Fuel pressure regulator (Refer to Testing and Inspection.)
- Fuel lines
- Fuel filter for clogging
>> Repair or replace.
12.CHECK IGNITION TIMING
Check the following items. Refer to Basic Inspection.





OK or NG
OK - GO TO 13.
NG - Follow the Basic Inspection.
13.CHECK A/F SENSOR 1 INPUT SIGNAL
1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.





3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.





Continuity should exist.

5. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.





Continuity should not exist.

6. Also check harness for short to power.
OK or NG
OK - GO TO 14.
NG - Repair open circuit or short to ground or short to power in harness or connectors.
14.CHECK A/F SENSOR 1 HEATER
Refer to P0031.
OK or NG
OK - GO TO 16.
NG - GO TO 15.
15.REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace malfunctioning air fuel ratio (A/F) sensor 1.

CAUTION:
- Discard any air fuel ratio (A/F) sensor which has been dropped from a height of more than 0.5 m
(19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new air fuel ratio (A/F) sensor, clean exhaust system threads (using Oxygen Sensor
Thread Cleaner tool J-43897-18 or J-43897-12) and approved anti-seize lubricant.
>> INSPECTION END
16.CHECK MASS AIR FLOW SENSOR
With CONSULT-III
Check mass air flow sensor signal in "DATA MONITOR" mode with CONSULT-III.

3.0 - 9.0 gm/sec: at idling
9.0 - 28.0 gm/sec: at 2,500 rpm

With GST
Check mass air flow sensor signal in Service $01 with GST.

3.0 - 9.0 gm/sec: at idling
9.0 - 28.0 gm/sec: at 2,500 rpm

OK or NG
OK - GO TO 17.
NG - Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to P0101 P0101 P0101 .
17.CHECK SYMPTOM MATRIX CHART
Check items on the rough idle symptom in Symptom Related Diagnostic Procedures.
OK or NG
OK - GO TO 18.
NG - Repair or replace.
18.ERASE THE 1ST TRIP DTC
Some tests may cause a 1st trip DTC to be set.
Erase the 1st trip DTC from the ECM memory after performing the tests. Refer to Testing and Inspection.
>> GO TO 19.
19.CHECK INTERMITTENT INCIDENT
Refer to How to Check Terminal and Intermittent Incident.
>> INSPECTION END