P0307
2UR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0300-P0308: 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
DTC P0305 - Cylinder 5 Misfire Detected
DTC P0306 - Cylinder 6 Misfire Detected
DTC P0307 - Cylinder 7 Misfire Detected
DTC P0308 - Cylinder 8 Misfire Detected
DESCRIPTION
When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause an increase in exhaust emission levels. 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 exceeds the threshold levels and may cause emission deterioration, the ECM illuminates the MIL and sets a DTC.
If DTCs that indicate misfires are set for different cylinders, but DTC P0300 is not set, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only set when several misfiring cylinders are detected at the same time.
MONITOR DESCRIPTION
The ECM illuminates the MIL and sets 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 of the engine starting, an excessive misfiring rate (approximately 30 to 60 misfires per 1000 crankshaft revolutions) occurs once.
- After the first 1000 crankshaft revolutions, an excessive misfiring rate (approximately 30 to 60 misfires per 1000 crankshaft revolutions) occurs 4 times in sequential crankshaft revolutions.
The ECM flashes the MIL and sets a DTC when either one of the following conditions, which could cause Three-Way Catalytic Converter (TWC) damage, is detected (2 trip detection logic):
- In every 200 crankshaft revolutions at a high engine rpm, the threshold misfiring percentage is recorded once.
- In every 200 crankshaft revolutions at a normal engine rpm, the threshold misfiring percentage is recorded 3 times.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
Misfire:
Monitor period of emission-related-misfire:
Monitor period of catalyst-damaged-misfire (MIL blinks):
TYPICAL MALFUNCTION THRESHOLDS
Monitor period of emission-related-misfire:
Monitor period of catalyst-damage-misfire (MIL blinks):
MONITOR RESULT
Refer to CHECKING MONITOR STATUS Mode 6 Data.
CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the power switch on (READY).
3. Turn the Techstream ON.
4. Record the DTC(s) and freeze frame data.
5. Using the Techstream, switch the ECM from normal mode to check mode Inspection Mode Procedure.
6. Read the misfire counts of each cylinder, Cylinder #1 Misfire Count to Cylinder #8 Misfire Count with the engine in an idling condition. If any misfire count is displayed, skip the following confirmation driving pattern.
7. Drive the vehicle several times with the conditions, such as engine rpm and engine load, shown in Misfire RPM and Misfire Load in the Data List.
HINT
- In order to store misfire DTCs using the Misfire RPM and Misfire Load in the Data List, it is necessary to operate the vehicle for the period of time shown in the table below.
8. Check whether misfires have occurred by checking DTCs and freeze frame data.
HINT
Do not turn the power switch off until the stored 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 will be erased.
9. Record the DTC(s), freeze frame data and misfire counts.
10. Turn the power switch off and wait for at least 5 seconds.
INSPECTION PROCEDURE
HINT
- If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
- When viewed from the rear of the engine assembly, Bank 1 is on the left side and Bank 2 is on the right side.
- 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 is 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 #8 Misfire Count.
- Be sure to confirm that no misfiring cylinder DTCs are set again by conducting the confirmation driving pattern after finishing repairs.
- For 6 and 8 cylinder engines, the ECM intentionally does not set the specific misfiring cylinder DTCs at high engine RPM. If misfires occur only in high engine RPM areas, only DTC P0300 is set.
In the event of DTC P0300 being present, perform the following operations:
(1) Clear the DTC DTC Check / Clear.
(2) Turn the power switch on (READY).
(3) Conduct the confirmation driving pattern.
(4) Read the misfiring rates of each cylinder or DTC(s) using the Techstream.
(5) Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.
(6) After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300 is not set.
- 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 the Coolant Temp in the freeze frame data is less than 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 detection.
PROCEDURE
1. CHECK ANY OTHER DTC OUTPUT (IN ADDITION TO MISFIRE DTCS)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream ON.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
Result
HINT
If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART 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) Put the engine in inspection mode Inspection Mode Procedure.
(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 MISFIRE COUNT OF PORT INJECTION
(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Turn the Techstream ON.
(d) Clear DTCs DTC Check / Clear.
(e) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Way / Port. (Procedure "A")
(f) Allow the engine to idle.
(g) Monitor all of the misfire rate values that are displayed on the Techstream: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.
If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")
(1) Move the shift lever to the D position.
(2) Repeat procedure "A" to "B" above.
(3) Monitor all of the misfire rate values that are displayed on the Techstream.
Result
B -- CHECK MISFIRE COUNT OF DIRECT INJECTION
A -- Continue to next step.
4. CHECK MISFIRE COUNT OF DIRECT INJECTION
(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Turn the Techstream ON.
(d) Clear DTCs DTC Check / Clear.
(e) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Way / Direct. (Procedure "A")
(f) Allow the engine to idle.
(g) Monitor all of the misfire rate values that are displayed on the Techstream: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.
If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")
(1) Move the shift lever to the D position.
(2) Repeat procedure "A" to "B" above.
(3) Monitor all of the misfire rate values that are displayed on the Techstream.
Result
D -- CHECK FUEL PRESSURE (LOW PRESSURE SIDE)
C -- REPLACE FUEL INJECTOR FOR PORT INJECTION (MISFIRING CYLINDER) Removal
B -- CHECK PCV HOSE (HOSE CONNECTIONS)
A -- Continue to next step.
5. CHECK SPARK PLUG
(a) Check the spark plug Testing and Inspection.
NG -- REPLACE SPARK PLUG Removal
OK -- Continue to next step.
6. CHECK FOR SPARK AND IGNITION
(a) Perform a spark test Testing and Inspection.
CAUTION:
Always disconnect each injector connector.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Sparks jump across the electrode gap.
NG -- CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
OK -- Continue to next step.
7. CHECK CYLINDER COMPRESSION PRESSURE (MALFUNCTIONING CYLINDER)
(a) Measure the cylinder compression pressure of the misfiring cylinder Engine.
NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- REPLACE ECM Removal
8. 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 Testing and Inspection.
CAUTION:
Always disconnect each injector connector.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Sparks jump across the electrode gap.
NG -- REPLACE IGNITION COIL ASSEMBLY THEN CONFIRM THAT THERE IS NO MISFIRE Removal
OK -- REPLACE SPARK PLUG Removal
9. CHECK PCV HOSE (HOSE CONNECTIONS)
OK:
PCV hose is connected correctly and is not damaged.
NG -- REPAIR OR REPLACE PCV HOSE Removal
OK -- Continue to next step.
10. CHECK AIR INDUCTION SYSTEM
(a) Check the air induction system for vacuum leakage.
OK:
No leakage from air induction system.
NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM Removal
OK -- Continue to next step.
11. READ VALUE USING TECHSTREAM (COOLANT TEMP)
(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Turn the Techstream ON.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
(e) Read the Data List twice, when the engine is both cold and warmed up.
Standard:
With cold engine
Same as ambient air temperature
With warm engine
Between 75°C and 95°C (167°F and 203°F)
NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.
12. INSPECT MASS AIR FLOW METER (for Bank 1 and Bank 2)
(a) Inspect the mass air flow meter On-Vehicle Inspection.
NG -- REPLACE MASS AIR FLOW METER Removal
OK -- Continue to next step.
13. CHECK VALVE TIMING P0016
NG -- ADJUST VALVE TIMING
OK -- REPLACE ECM Removal
14. CHECK FUEL PRESSURE (LOW PRESSURE SIDE)
(a) Check the fuel pressure (low pressure side) Testing and Inspection.
NG -- CHECK FUEL PUMP OPERATION
OK -- REPLACE FUEL INJECTOR FOR PORT INJECTION Removal
15. CHECK FUEL PUMP OPERATION
(a) Check the fuel pump operation Fuel Pump.
NG -- REPLACE FUEL PUMP Removal
OK -- CHECK AND REPLACE FUEL SYSTEM (PRESSURE REGULATOR, PIPE LINE AND FILTER)
16. CHECK MISFIRE COUNT OF DIRECT INJECTION
(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Turn the Techstream ON.
(d) Clear DTCs DTC Check / Clear.
(e) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Way / Direct. (Procedure "A")
(f) Allow the engine to idle.
(g) Monitor all of the misfire rate values that are displayed on the Techstream: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.
If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")
(1) Move the shift lever to the D position.
(2) Repeat procedure "A" to "B" above.
(3) Monitor all of the misfire rate values that are displayed on the Techstream.
Result
B -- CHECK MISFIRE COUNT
A -- REPLACE FUEL INJECTOR FOR DIRECT INJECTION (MALFUNCTIONING CYLINDER INJECTOR) Removal
17. CHECK MISFIRE COUNT
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (READY).
(c) Turn the Techstream ON.
(d) Clear DTCs DTC Check / Clear.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Misfire RPM, Misfire Load, Cylinder #1 Misfire Count to Cylinder #8 Misfire Count and Injection Way.
(f) Drive the vehicle with Misfire RPM and Misfire Load.
(g) Monitor all of the misfire rate values or DTCs and Injection Way displayed on the Techstream.
Result
D -- REPLACE FUEL INJECTOR FOR DIRECT INJECTION (MISFIRING CYLINDER) Removal
C -- CHECK PCV HOSE (HOSE CONNECTIONS)
B -- CHECK SPARK PLUG
A -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems