CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE CODES)
READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)
READ VALUE USING INTELLIGENT TESTER
CHECK CYLINDER COMPRESSION PRESSURE
CHECK HARNESS AND CONNECTOR (ECM - INJECTOR)
INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30, #40, #50 AND/OR #60 VOLTAGE)
CHECK FUEL INJECTOR OF MISFIRING CYLINDER
CHECK VALVE CLEARANCE OF MISFIRING CYLINDER
READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)
READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)
CHECK CYLINDER COMPRESSION PRESSURE
CHECK HARNESS AND CONNECTOR (ECM - INJECTOR)
INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30, #40, #50 AND/OR #60 VOLTAGE)
CHECK FUEL INJECTOR OF MISFIRING CYLINDER
CHECK VALVE CLEARANCE OF MISFIRING CYLINDER
REPLACE SPARK PLUG WITH NORMAL ONE AND CHECK SPARK OF MISFIRING CYLINDER
REPLACE IGNITION COIL WITH NORMAL ONE AND CHECK SPARK OF MISFIRING CYLINDER
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
Description DTC P0300 P0301 P0302 P0303 P0304 P0305 P0306
When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. High HC concentration levels can cause an 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 count. 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 VVT sensor and the Crankshaft Position (CKP) sensor. The VVT 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, the ECM illuminates the MIL and stores a DTC.
| DTC Code | DTC Detection Condition | Trouble Area |
| P0300 | Simultaneous misfiring of several cylinders occurs and one of the following conditions below is detected (2 trip detection logic):
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| P0301 P0302 P0303 P0304 P0305 P0306 | Misfiring of specific cylinder occurs and one of following conditions below is detected (2 trip detection logic):
|
When multiple DTCs for misfiring cylinders are 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.
Wiring diagram
Confirmation driving pattern
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to ON.
- Turn the intelligent tester on.
- Record the DTC(s) and freeze frame data.
- Using the intelligent tester, switch the ECM from normal mode to check mode.
- Read the misfire count of each cylinder (Cylinder #1 Misfire Count to Cylinder #6 Misfire Count) with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.
- If no misfire counts are displayed, drive the vehicle several times at the engine speed and engine load, etc., recorded in the freeze frame data.
HINT:
- In order to store misfire DTCs, drive the vehicle at the engine speed and engine load, etc., recorded in the freeze frame data for the time specified in the table below.
Engine Speed Duration Idling 3.5 minutes or more 1000 3 minutes or more 2000 1.5 minutes or more 3000 1 minute or more - Check whether misfires have occurred by checking DTCs and freeze frame data.
HINT:
Do not turn the ignition 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 are cleared.
- Record the DTC(s), freeze frame data and misfire count.
- Turn the ignition 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.
- Read freeze frame data using the intelligent tester. 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 can be considered to be a possible cause of the problem:
- There was insufficient fuel volume in the tank.
- Improper fuel was used.
- The spark plugs have been contaminated.
- After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfire Count to Cylinder #6 Misfire Count).
- Be sure to confirm that no misfiring cylinder DTCs are stored again by conducting the confirmation driving pattern after finishing repairs.
- For 6 and 8 cylinder engines, the ECM intentionally does not store the specific misfiring cylinder DTCs at high engine speeds. If misfires occur only in high engine speed areas, only DTC P0300 is stored. In the event of DTC P0300 being present, perform the following operations:
- Clear the DTCs.
- Start the engine and conduct the confirmation driving pattern.
- Read the misfiring rates of each cylinder or DTC(s) using the intelligent tester.
- Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.
- After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300 is not stored.
- 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 misfire may have occurred only while warming up the engine.
- An extremely imbalanced drive wheel can cause body vibration, which may cause misfire DTC(s) to be stored.
1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE CODES)
-
Connect the intelligent tester to the DLC3.
-
Turn the ignition switch to ON.
-
Turn the intelligent tester on.
-
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
-
Read DTCs.
HINT:
Write down the DTCs.
Result Display (DTC Output) Proceed to P0300, P0301, P0302, P0303, P0304, P0305 and/or P0306 A P0300, P0301, P0302, P0303, P0304, P0305 and/or P0306 and other DTCs B
HINT:
If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305 and P0306 are output, troubleshoot those DTCs first.
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| A | |
2.READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)
-
Connect the intelligent tester to the DLC3.
-
Turn the ignition switch to ON and turn the intelligent tester on.
-
Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Misfire RPM and Misfire Load.
-
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 | |
3.CHECK PCV HOSE CONNECTIONS
-
Check the PCV hose connections.
OK:
PCV hose is correctly connected and is not damaged.
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| OK | |
4.READ VALUE USING INTELLIGENT TESTER
- (a) Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count, #2, #3, #4, #5 and #6.
- (b) Read the value for Cylinder #1 Misfire Count to Cylinder #6 Misfire Count displayed on the intelligent tester. If no misfire counts occur in any cylinders, perform the following procedures:
- (1) Start the engine and let it idle.
- (2) Move the shift lever to D.
- (3) Check the Cylinder #1 Misfire Count to Cylinder #6 Misfire Count.
- (4) If misfire counts are still not displayed, perform steps (c) and (d).
- (c) Drive the vehicle with the Misfire RPM and Misfire Load noted in the "Read value using intelligent tester (Misfire RPM and Misfire Load)" procedures above.
- (d) Read the Cylinder #1 Misfire Count to Cylinder #6 Misfire Count or DTCs displayed on the intelligent tester.
Result Misfire Count Proceed to Most misfires occur in only 1 or 2 cylinders A 3 cylinders or more have equal misfire counts B 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's 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's record of Engine Run Time is below 120 seconds, the misfire may be detected immediately after the engine is started.
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| A | |
5.CHECK SPARK PLUG
-
Remove the ignition coil and the spark plug of the misfiring cylinder.
-
Measure the spark plug electrode gap.
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| OK | |
6.CHECK FOR SPARKS AND IGNITION
-
Disconnect the injector connectors to prevent the engine from starting.
CAUTION:
Always disconnect all injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
-
Remove the ignition coil from the cylinder head.
-
Install the spark plug to the ignition coil.
-
Attach the spark plug assembly to the cylinder head.
-
Crank the engine for less than 2 seconds and check for sparks.
OK:
Sparks jump across electrode gap.
-
Install the ignition coil.
-
Reconnect the injector connectors.
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| OK | |
7.CHECK CYLINDER COMPRESSION PRESSURE
-
Measure the cylinder compression pressure of the misfiring cylinder.
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| OK | |
8.CHECK HARNESS AND CONNECTOR (ECM - INJECTOR)
-
Disconnect the injector connector (of the misfiring cylinder).
-
Disconnect the ECM connector.
-
Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Cylinder Tester Connection Switch Condition Specified Condition No. 1 C5-1 - Body ground Ignition switch ON 11 to 14 V No. 2 C16-1 - Body ground Ignition switch ON 11 to 14 V No. 3 C7-1 - Body ground Ignition switch ON 11 to 14 V No. 4 C14-1 - Body ground Ignition switch ON 11 to 14 V No. 5 C9-1 - Body ground Ignition switch ON 11 to 14 V No. 6 C12-1 - Body ground Ignition switch ON 11 to 14 V
-
Measure the resistance according to the value(s) in the table below.
Standard Resistance:
for LHD Cylinder Tester Connection Condition Specified Condition No. 1 C5-2 - Body ground Always 10 k? or higher C5-2 - C45-45 (#10) Always Below 1 ? No. 2 C16-2 - Body ground Always 10 k? or higher C16-2 - C45-85 (#20) Always Below 1 ? No. 3 C7-2 - Body ground Always 10 k? or higher C7-2 - C45-44 (#30) Always Below 1 ? No. 4 C14-2 - Body ground Always 10 k? or higher C14-2 - C45-84 (#40) Always Below 1 ? No. 5 C9-2 - Body ground Always 10 k? or higher C9-2 - C45-43 (#50) Always Below 1 ? No. 6 C12-2 - Body ground Always 10 k? or higher C12-2 - C45-83 (#60) Always Below 1 ? for RHD Cylinder Tester Connection Condition Specified Condition No. 1 C5-2 - Body ground Always 10 k? or higher C5-2 - C46-45 (#10) Always Below 1 ? No. 2 C16-2 - Body ground Always 10 k? or higher C16-2 - C46-85 (#20) Always Below 1 ? No. 3 C7-2 - Body ground Always 10 k? or higher C7-2 - C46-44 (#30) Always Below 1 ? No. 4 C14-2 - Body ground Always 10 k? or higher C14-2 - C46-84 (#40) Always Below 1 ? No. 5 C9-2 - Body ground Always 10 k? or higher C9-2 - C46-43 (#50) Always Below 1 ? No. 6 C12-2 - Body ground Always 10 k? or higher C12-2 - C46-83 (#60) Always Below 1 ?
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| OK | |
9.INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30, #40, #50 AND/OR #60 VOLTAGE)
-
Disconnect the ECM connector.
-
Measure the voltage according to the value(s) in the table below.
Standard Voltage:
for LHD Tester Connection Switch Condition Specified Condition C45-45 (#10) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-85 (#20) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-44 (#30) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-84 (#40) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-43 (#50) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-83 (#60) - C45-22 (E01) Ignition switch ON 11 to 14 V for RHD Tester Connection Switch Condition Specified Condition C46-45 (#10) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-85 (#20) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-44 (#30) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-84 (#40) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-43 (#50) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-83 (#60) - C46-22 (E01) Ignition switch ON 11 to 14 V
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| OK | |
10.CHECK FUEL INJECTOR OF MISFIRING CYLINDER
-
Check the injector injection (whether fuel volume is large or small, and whether injection pattern is poor).
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| OK | |
11.CHECK VALVE CLEARANCE OF MISFIRING CYLINDER
-
Check the valve clearance.
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| OK | |
12.CHECK AIR INDUCTION SYSTEM
-
Check the air induction system for vacuum leakage.
OK:
No leakage from air induction system.
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| OK | |
13.CHECK VALVE TIMING
-
Remove the cylinder head cover.
-
Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.
-
Check that the timing marks of the camshaft timing gears are aligned with the timing marks of the bearing cap as shown in the illustration.
If not, turn the crankshaft 1 revolution (360°), then align the marks as above.
OK:
Timing marks on camshaft timing gears are aligned as shown in the illustration.
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| OK | |
14.CHECK FUEL PRESSURE
-
Check the fuel pressure.
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| OK | |
15.READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)
-
Connect the intelligent tester to the DLC3.
-
Turn the ignition switch to ON and turn the intelligent tester on.
-
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
-
Read the Data List twice, when the engine is cold and when it is warmed up.
Standard:
With cold engine: Same as ambient air temperature. With warm engine: 80 to 100°C (176 to 212°F).
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| OK | |
16.INSPECT MASS AIR FLOW METER
-
Inspect the mass air flow meter.
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| OK | |
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17.CHECK AIR INDUCTION SYSTEM
-
Check the air induction system for vacuum leakage.
OK:
No leakage from air induction system.
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| OK | |
18.CHECK VALVE TIMING
-
Remove the cylinder head cover.
-
Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.
-
Check that the timing marks of the camshaft timing gears are aligned with the timing marks of the bearing cap as shown in the illustration.
If not, turn the crankshaft 1 revolution (360°), then align the marks as above.
OK:
Timing marks on camshaft timing gears are aligned as shown in the illustration.
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| OK | |
19.CHECK FUEL PRESSURE
-
Check the fuel pressure.
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| OK | |
20.READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)
-
Connect the intelligent tester to the DLC3.
-
Turn the ignition switch to ON and turn the intelligent tester on.
-
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
-
Read the Data List twice, when the engine is cold and when it is warmed up.
Standard:
With cold engine: Same as ambient air temperature. With warm engine: 80 to 100°C (176 to 212°F).
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| OK | |
21.INSPECT MASS AIR FLOW METER
-
Inspect the mass air flow meter.
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| OK | |
22.CHECK SPARK PLUG
-
Remove the ignition coil and the spark plug of the misfiring cylinder.
-
Measure the spark plug electrode gap.
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| OK | |
23.CHECK FOR SPARKS AND IGNITION
-
Disconnect the injector connectors to prevent the engine from starting.
CAUTION:
Always disconnect all injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
-
Remove the ignition coil from the cylinder head.
-
Install the spark plug to the ignition coil.
-
Attach the spark plug assembly to the cylinder head.
-
Crank the engine for less than 2 seconds and check for sparks.
OK:
Sparks jump across electrode gap.
-
Install the ignition coil.
-
Reconnect the injector connectors.
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| OK | |
24.CHECK CYLINDER COMPRESSION PRESSURE
-
Measure the cylinder compression pressure of the misfiring cylinder.
|
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||||
| OK | |
25.CHECK HARNESS AND CONNECTOR (ECM - INJECTOR)
-
Disconnect the injector connector (of the misfiring cylinder).
-
Disconnect the ECM connector.
-
Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Cylinder Tester Connection Switch Condition Specified Condition No. 1 C5-1 - Body ground Ignition switch ON 11 to 14 V No. 2 C16-1 - Body ground Ignition switch ON 11 to 14 V No. 3 C7-1 - Body ground Ignition switch ON 11 to 14 V No. 4 C14-1 - Body ground Ignition switch ON 11 to 14 V No. 5 C9-1 - Body ground Ignition switch ON 11 to 14 V No. 6 C12-1 - Body ground Ignition switch ON 11 to 14 V
-
Measure the resistance according to the value(s) in the table below.
Standard Resistance:
for LHD Cylinder Tester Connection Condition Specified Condition No. 1 C5-2 - Body ground Always 10 k? or higher C5-2 - C45-45 (#10) Always Below 1 ? No. 2 C16-2 - Body ground Always 10 k? or higher C16-2 - C45-85 (#20) Always Below 1 ? No. 3 C7-2 - Body ground Always 10 k? or higher C7-2 - C45-44 (#30) Always Below 1 ? No. 4 C14-2 - Body ground Always 10 k? or higher C14-2 - C45-84 (#40) Always Below 1 ? No. 5 C9-2 - Body ground Always 10 k? or higher C9-2 - C45-43 (#50) Always Below 1 ? No. 6 C12-2 - Body ground Always 10 k? or higher C12-2 - C45-83 (#60) Always Below 1 ? for RHD Cylinder Tester Connection Condition Specified Condition No. 1 C5-2 - Body ground Always 10 k? or higher C5-2 - C46-45 (#10) Always Below 1 ? No. 2 C16-2 - Body ground Always 10 k? or higher C16-2 - C46-85 (#20) Always Below 1 ? No. 3 C7-2 - Body ground Always 10 k? or higher C7-2 - C46-44 (#30) Always Below 1 ? No. 4 C14-2 - Body ground Always 10 k? or higher C14-2 - C46-84 (#40) Always Below 1 ? No. 5 C9-2 - Body ground Always 10 k? or higher C9-2 - C46-43 (#50) Always Below 1 ? No. 6 C12-2 - Body ground Always 10 k? or higher C12-2 - C46-83 (#60) Always Below 1 ?
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| OK | |
26.INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30, #40, #50 AND/OR #60 VOLTAGE)
-
Disconnect the ECM connector.
-
Measure the voltage according to the value(s) in the table below.
Standard Voltage:
for LHD Tester Connection Switch Condition Specified Condition C45-45 (#10) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-85 (#20) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-44 (#30) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-84 (#40) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-43 (#50) - C45-22 (E01) Ignition switch ON 11 to 14 V C45-83 (#60) - C45-22 (E01) Ignition switch ON 11 to 14 V for RHD Tester Connection Switch Condition Specified Condition C46-45 (#10) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-85 (#20) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-44 (#30) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-84 (#40) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-43 (#50) - C46-22 (E01) Ignition switch ON 11 to 14 V C46-83 (#60) - C46-22 (E01) Ignition switch ON 11 to 14 V
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| OK | |
27.CHECK FUEL INJECTOR OF MISFIRING CYLINDER
-
Check the injector injection.
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|
||||
| OK | |
28.CHECK VALVE CLEARANCE OF MISFIRING CYLINDER
-
Check the valve clearance.
|
|
||||
| OK | |
|
29.REPLACE SPARK PLUG WITH NORMAL ONE AND CHECK SPARK OF MISFIRING CYLINDER
-
Replace the installed spark plug with a spark plug that functions normally.
-
Perform a spark test.
CAUTION:
Always disconnect all injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
-
Install the spark plug to the ignition coil and connect the ignition coil connector.
-
Disconnect all the injector connectors.
-
Ground the spark plug.
-
Check if sparks occur while the engine is being cranked.
OK:
Sparks jump across electrode gap.
-
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|
||||
| OK | |
|
30.REPLACE IGNITION COIL WITH NORMAL ONE AND CHECK SPARK OF MISFIRING CYLINDER
-
Replace the installed ignition coil with a ignition coil that functions normally.
-
Perform a spark test.
CAUTION:
Always disconnect all injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
-
Install the spark plug to the ignition coil and connect the ignition coil connector.
-
Disconnect all the injector connectors.
-
Ground the spark plug.
-
Check if sparks occur while the engine is being cranked.
OK:
Sparks jump across electrode gap.
-
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||||
| OK | |
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