P0303

2AR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0300-P0304: Random / Multiple Cylinder Misfire Detected

DTC P0300 - Random / Multiple Cylinder Misfire Detected

DTC P0301 - Cylinder 1 Misfire Detected

DTC P0302 - Cylinder 2 Misfire Detected

DTC P0303 - Cylinder 3 Misfire Detected

DTC P0304 - Cylinder 4 Misfire Detected

DESCRIPTION

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. High HC concentration levels can cause increase in exhaust emission levels. Extremely high concentrations of HC can also cause increases in the Three-Way Catalytic Converter (TWC) temperature, which may cause damage to the TWC. To prevent this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the TWC reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the Camshaft Position (CMP) sensor and the Crankshaft Position (CKP) sensor. The CMP sensor is used to identify any misfiring cylinders and the CKP sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds. If the misfire count exceeds the threshold levels, and could cause emission deterioration, the ECM illuminates the MIL and stores a DTC.

When DTCs for misfiring cylinders are randomly stored, but DTC P0300 is not stored, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only stored when several misfiring cylinders are detected at the same time.

MONITOR DESCRIPTION

The ECM illuminates the MIL and stores a DTC when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).

* Within the first 1000 crankshaft revolutions after the engine starts, an excessive number of misfires (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs once.

* An excessive number of misfires (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

The ECM flashes the MIL and stores a DTC when either one of the following conditions, which could cause damage to the Three-Way Catalytic Converter (TWC), is detected (2 trip detection logic).

HINT
If a catalyst-damaging misfire occurs, the monitor informs the driver by blinking the MIL (1 trip).

* In every 200 crankshaft revolutions at a high engine speed, the threshold misfiring percentage is recorded once.

* In every 200 crankshaft revolutions at a normal engine speed, the threshold misfiring percentage is recorded 3 times.

The ECM illuminates the MIL and stores a DTC when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).

Misfire Monitor for Mexico Models

* Within the first 1000 crankshaft revolutions after the engine starts, an excessive number of misfires (approximately 1000 misfires per 1000 crankshaft revolutions) occurs once.

* An excessive number of misfires (approximately 500 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

The ECM flashes the MIL and stores a DTC when the following condition, which could cause the Three-Way Catalytic Converter (TWC) damage, is detected (2 trip detection logic).

* A catalyst-damaging misfire, which is monitored every 200 crankshaft revolutions, occurs 3 times.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

Misfire:

Monitor period of emission-related misfire:

Monitor period of catalyst-damaging misfire (MIL blinks):

TYPICAL MALFUNCTION THRESHOLDS

Monitor period of emission-related misfire:

Monitor period of catalyst-damaging misfire (MIL blinks):

MONITOR RESULT

Refer to Checking Monitor Status Mode 6 Data.

WIRING DIAGRAM

Wiring diagram of the ignition system.

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the Techstream on.

4. Record the DTC(s) and freeze frame data.

5. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

6. Using the Techstream, switch the ECM from normal mode to check mode Check Mode Procedure.

7. Read the misfire counts of each cylinder, Cylinder #1 Misfire Count to Cylinder #4 Misfire Count, with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.

8. Drive the vehicle so that the vehicle conditions displayed in Misfire RPM and Misfire Load of the Data List are the same as the freeze frame data. Perform this step several times.

HINT
In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below, confirm the Misfire RPM and Misfire Load in the Data List.

9. Check whether misfires have occurred by checking DTCs and freeze frame data.

HINT
Do not turn the ignition switch off until the output DTC(s) and freeze frame data have been recorded. When the ECM returns to normal mode (default), the stored DTC(s), freeze frame data and other data are cleared.

10. Record the DTC(s), freeze frame data and misfire counts.

11. Turn the ignition switch off and wait for at least 15 seconds.

12. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

INSPECTION PROCEDURE

HINT
- If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
- Read freeze frame data using the Techstream. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
- If the misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the ECM as freeze frame data.
- If the misfire still cannot be reproduced even though the conditions stored in the ECM as freeze frame data have been reproduced, one of the following factors is considered to be a possible cause of the problem:
(1) There was insufficient fuel in the tank.
(2) Improper fuel was used.
(3) The spark plugs have been contaminated.
(4) The problem requires further diagnosis.
- After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfire Count to Cylinder #4 Misfire Count).
- Be sure to confirm that no misfiring cylinder DTCs are stored again by conducting the confirmation driving pattern after finishing repairs.
- When one of Short FT #1, Long FT #1, Short FT #2 or Long FT #2 in the freeze frame data is outside the range of +/-20%, the air-fuel ratio may be rich (-20% or less) or lean (+20% or more).
- When Coolant Temp in the freeze frame data is below 75°C (167°F), the misfires have occurred only while warming up the engine.
- An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be stored.

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE DTCS)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(e) Read DTCs.

HINT
Write down the output DTCs.

Result

HINT
If any DTCs other than P0300, P0301, P0302, P0303 and P0304 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART Engine Control System - SFI System
A -- Continue to next step.

2. READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Misfire RPM and Misfire Load.

(e) Read and note the Misfire RPM and Misfire Load values.

HINT
The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.

NEXT -- Continue to next step.

3. CHECK PCV HOSE CONNECTIONS

(a) Check the PCV hose connections.

OK:

PCV hose is correctly connected and is not damaged.

NG -- REPAIR OR REPLACE PCV HOSE Removal
OK -- Continue to next step.

4. READ VALUE USING TECHSTREAM (CATALYST OT MF F/C)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Catalyst OT MF F/C.

(e) Read the value displayed on the Techstream.

Result

B -- READ VALUE USING TECHSTREAM (CYLINDER MISFIRE COUNT)
A -- Continue to next step.

5. PERFORM ACTIVE TEST USING TECHSTREAM (PROHIBIT CAT OT F/C)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Prohibit the Catalyst OT Misfire prevent F/C.

(e) Perform the Active Test.

NOTICE:
When performing the Active Test, make sure the vehicle is stopped and the engine is either idling or being revved within 3000 rpm.

NEXT -- Continue to next step.

6. READ VALUE USING TECHSTREAM (CYLINDER MISFIRE COUNT)

(a) Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count, Cylinder #2 Misfire Count, Cylinder #3 Misfire Count and Cylinder #4 Misfire Count.

(b) Start the engine and allow the engine to idle.

(c) Read each value for Cylinder #1 Misfire Count to Cylinder #4 Misfire Count displayed on the Techstream. If no misfire counts occur in any cylinders, perform steps (d) and (e) and then check the misfire counts again.

(d) Drive the vehicle with the Misfire RPM and Misfire Load noted in the "READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)" procedures above.

(e) Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the Techstream.

Result

HINT
- If it is difficult to reproduce misfires for each cylinder, check the Data List item called Misfire Margin. Try to find vehicle driving conditions that lower the Misfire Margin value. Values above 30% are considered normal.
- If the freeze frame data record of the ECT is below 75°C (167°F), the misfire may be detected only when the engine is cold.
- If the freeze frame data record of the Engine Run Time is below 120 seconds, the misfire may be detected immediately after the engine is started.

B -- CHECK AIR INDUCTION SYSTEM
A -- Continue to next step.

7. INSPECT SPARK PLUG

(a) Remove the ignition coil and spark plug from the misfiring cylinder.

(b) Measure the spark plug electrode gap.

Electrode gap for a new spark plug:

1.0 to 1.1 mm (0.039 to 0.043 in.)

Maximum electrode gap for a used spark plug:

1.3 mm (0.051 in.)

NOTICE:
If the electrode gap is more than 1.3 mm (0.051 in.), replace the spark plug. Do not adjust the electrode gap.

Recommended Spark Plug

(c) Check the electrode for carbon deposits.

NOTICE:
If necessary, clean the spark plug.

(d) Reinstall the ignition coil and spark plug.

NG -- REPLACE SPARK PLUG Removal
OK -- Continue to next step.

8. CHECK FOR SPARKS AND IGNITION

(a) Disconnect the injector connectors to prevent the engine from starting.

CAUTION:
Always disconnect all the injector connectors.

(b) Remove the ignition coil from the cylinder head.

(c) Install the spark plug onto the ignition coil.

(d) Attach the spark plug assembly to the cylinder head.

(e) Crank the engine for less than 2 seconds and check the spark.

NOTICE:
Do not crank the engine for more than 2 seconds.

OK:

Sparks jump across electrode gap.

(f) Install the ignition coil.

(g) Reconnect the injector connectors.

NG -- CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
OK -- Continue to next step.

9. CHECK CYLINDER COMPRESSION PRESSURE

(a) Measure the cylinder compression pressure of the misfiring cylinder Engine.

NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- Continue to next step.

10. INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30 AND/OR #40 VOLTAGE)

(a) Disconnect the ECM connector.

(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

(d) Reconnect the ECM connector.

NG -- GO TO FUEL INJECTOR CIRCUIT Fuel Injector Circuit
OK -- Continue to next step.

11. CHECK FUEL INJECTOR OF MISFIRING CYLINDER

(a) Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.

NG -- REPLACE FUEL INJECTOR Removal
OK -- Continue to next step.

12. CHECK AIR INDUCTION SYSTEM

(a) Check the air induction system for vacuum leakage Intake System.

OK:

No leakage from air induction system.

NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM Removal
OK -- Continue to next step.

13. CHECK INTAKE AIR CONTROL VALVE (for TCV)

(a) Check the intake air control valve for TCV Intake System.

NG -- REPLACE INTAKE AIR CONTROL VALVE (for TCV) Removal
OK -- Continue to next step.

14. CHECK VALVE TIMING P0011

NG -- ADJUST VALVE TIMING Installation
OK -- Continue to next step.

15. CHECK FUEL PRESSURE

(a) Check the fuel pressure Fuel System.

NG -- REPAIR OR REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE OR FILTER
OK -- Continue to next step.

16. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171

NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.

17. INSPECT MASS AIR FLOW METER P0171

NG -- REPLACE MASS AIR FLOW METER Removal

OK -- REPLACE ECM Removal

18. CHECK AIR INDUCTION SYSTEM

(a) Check the air induction system for vacuum leakage Intake System.

OK:

No leakage from air induction system.

NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM Removal
OK -- Continue to next step.

19. CHECK INTAKE AIR CONTROL VALVE (for TCV)

(a) Check the intake air control valve for TCV Intake System.

NG -- REPLACE INTAKE AIR CONTROL VALVE (for TCV) Removal
OK -- Continue to next step.

20. CHECK VALVE TIMING P0011

NG -- ADJUST VALVE TIMING Installation
OK -- Continue to next step.

21. CHECK FUEL PRESSURE

(a) Check the fuel pressure Fuel System.

NG -- REPAIR OR REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE OR FILTER
OK -- Continue to next step.

22. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171

NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.

23. INSPECT MASS AIR FLOW METER P0171

NG -- REPLACE MASS AIR FLOW METER Removal
OK -- Continue to next step.

24. INSPECT SPARK PLUG

(a) Disconnect the injector connectors to prevent the engine from starting.

CAUTION:
Always disconnect all the injector connectors.

(b) Remove the ignition coil from the cylinder head.

(c) Install the spark plug onto the ignition coil.

(d) Attach the spark plug assembly to the cylinder head.

(e) Crank the engine for less than 2 seconds and check the spark.

NOTICE:
Do not crank the engine for more than 2 seconds.

OK:

Sparks jump across electrode gap.

(f) Install the ignition coil.

(g) Reconnect the injector connectors.

NG -- CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
OK -- Continue to next step.

26. CHECK CYLINDER COMPRESSION PRESSURE

(a) Measure the cylinder compression pressure of the misfiring cylinder Engine.

NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- Continue to next step.

27. INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30 AND/OR #40 VOLTAGE)

(a) Disconnect the ECM connector.

(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

(d) Reconnect the ECM connector.

NG -- GO TO FUEL INJECTOR CIRCUIT Fuel Injector Circuit
OK -- Continue to next step.

28. CHECK FUEL INJECTOR OF MISFIRING CYLINDER

(a) Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.

NG -- REPLACE FUEL INJECTOR Removal

OK -- REPLACE ECM Removal

29. CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER

(a) Change the installed spark plug to a spark plug that functions normally.

(b) Perform a spark test.

CAUTION:
Always disconnect all the injector connectors.

NOTICE:
Do not crank the engine for more than 2 seconds.

(1) Install the spark plug into the ignition coil and connect the ignition coil connector.

(2) Disconnect the injector connectors.

(3) Ground the spark plug.

(4) Check if sparks occur while the engine is being cranked.

OK:

Sparks jump across electrode gap.

NG -- CHANGE TO NORMAL IGNITION COIL AND CHECK SPARK OF MISFIRING CYLINDER

OK -- REPLACE SPARK PLUG Removal

30. CHANGE TO NORMAL IGNITION COIL AND CHECK SPARK OF MISFIRING CYLINDER

(a) Change the ignition coil to an ignition coil that functions normally.

(b) Perform a spark test.

CAUTION:
Always disconnect all the injector connectors.

NOTICE:
Do not crank the engine for more than 2 seconds.

(1) Install the spark plug into the ignition coil and connect the ignition coil connector.

(2) Disconnect the injector connectors.

(3) Ground the spark plug.

(4) Check if sparks occur while the engine is being cranked.

OK:

Sparks jump across electrode gap.

NG -- REPLACE ECM Removal

OK -- REPLACE IGNITION COIL Removal