P0300

P0300, P0301, P0302, P0303, P0304 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 first trip that 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 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 in any one cylinder or in 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 turn ignition switch OFF and wait at least 10 seconds before conducting the next test.

with SDT

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 "Diagnosis Procedure".

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 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.
Similar conditions to (1st trip) Freeze Frame Data mean that the following conditions should be satisfied at the same time.






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






with GST

Follow the procedure "WITH SDT" above.

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 SDT
1 Perform "POWER BALANCE" in "Active test" mode.
2 Is there any cylinder which does not produce a momentary engine speed drop?
Without SDT

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 9.

4. CHECK FUNCTION OF 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).

5. CHECK FUNCTION OF IGNITION COIL-I

CAUTION:
Never the following procedure in a place with no combustible objects and good ventilation.

1 Turn ignition switch OFF.
2 Remove fuel pump fuse in IPDM E/R to release fuel pressure.






NOTE:
Do not use SDT 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 three seconds, and check whether spark is generated between the spark plug and the grounded metal portion.






CAUTION:
- Never place the spark plug and the ignition coil within 50 cm (19.7 in) each other. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20 kV or more.
- It might damage the ignition coil if the gap of more than 17 mm is made.

NOTE:
When the gap is less than 13 mm, a 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 non-malfunctioning spark plug.
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.

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). Refer to [Ignition Coil: Removal and Installation] 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.






OK or NG
OK
INSPECTION END
NG
Replace spark plug(s) with standard type one(s). For spark plug type. Refer to [Ignition Coil: Removal and Installation] Removal and Installation.

9. CHECK COMPRESSION PRESSURE

Check compression pressure.

Refer to [Compression Pressure] 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 [Fuel Pressure Check: QR25DE] Testing and Inspection.
3 Install fuel pressure gauge kit [SST (J-44321)] and check fuel pressure. Refer to [Fuel Pressure Check: QR25DE] 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.
- Fuel pressure regulator (Refer to [Fuel Pressure Check: QR25DE] Testing and Inspection.)
- Fuel lines
- Fuel filter for clogging


Repair or replace.

12. CHECK IGNITION TIMING

Check the following items. Refer to [Basic Inspection] Basic Inspection.






OK or NG
OK
GO TO 13.
NG
Follow the [Basic Inspection] Basic Inspection.

13. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT

1 Turn ignition switch OFF.
2 Disconnect ECM harness connector and A/F sensor 1 harness connector.





3 Check harness continuity between the following terminals. Refer to Wiring Diagram.










4 Check harness continuity between ECM terminals 16, 35, 56, 75 or A/F sensor 1 terminals 1, 2, 5, 6 and ground. Refer to Wiring Diagram.






5 Also check harness for short to power.

OK or NG
OK
GO TO 14.
NG
Repair open circuit, short to ground or short to power in harness or connectors.

14. CHECK A/F SENSOR 1 HEATER

Refer to [P0031, P0032 A/F Sensor 1 Heater] P0031.

OK or NG
OK
GO TO 15.
NG
Replace A/F sensor 1. Refer to [Exhaust Manifold and Three Way Catalyst: Exploded View [QR25DE] Exhaust Manifold and Three Way Catalyst Exploded View ].

15. CHECK MASS AIR FLOW SENSOR

With SDT

Check "MASS AIR FLOW" in "Data list" mode with SDT.






With GST

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






OK or NG
OK
GO TO 16.
NG
Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. Refer to [Engine Control System Symptoms: Symptom Matrix Chart] P0101.

16. CHECK SYMPTOM MATRIX CHART

Check items on the rough idle symptom in Symptom Related Diagnostic Procedures.

OK or NG
OK
GO TO 17.
NG
Repair or replace.

17. 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 [DTC Index: ECM] DTC Index ECM.


GO TO 18.

18. CHECK INTERMITTENT INCIDENT

Perform [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.


INSPECTION END