Part 1
2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0300-P0306: 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
DESCRIPTION
When the engine misfires, high concentrations of hydrocarbons enter the exhaust gas. High hydrocarbons concentration levels can cause increase in exhaust emission levels. Extremely high concentrations of hydrocarbons can also cause increases in the three-way catalytic converter temperature, which may cause damage to the three-way catalytic converter. 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 three-way catalytic converter 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 sensor. The VVT sensor is used to identify any misfiring cylinders and the crankshaft position 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 sets a DTC.
When multiple DTCs for misfiring cylinders are set, 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 20 to 50 misfires per 1000 crankshaft revolutions) occurs once.
- An excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.
The ECM flashes the MIL and sets a DTC when either one of the following conditions, which could cause the three-way catalytic converter damage, is detected (2 trip detection logic).
- At a high engine rpm, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs once.
- At a normal engine rpm, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs 3 times.
HINT
If a catalyst damage misfire occurs, the ECM informs the driver by flashing the MIL.
Misfire Monitor for Mexico Models
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 1000 misfires per 1000 crankshaft revolutions) occurs once.
An excessive misfiring rate (approximately 500 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.
The ECM flashes the MIL and sets a DTC when the following condition, which could cause the Three-Way Catalytic Converter (TWC) damage, is detected (2 trip detection logic).
A catalyst damage 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-damaged-misfire (MIL blinks):
FOR MEXICO MODELS:
Misfire: for Mexico models
Monitor period of emission-related-misfire: for Mexico models
Monitor period of catalyst-damaged-misfire (MIL blinks): for Mexico models
TYPICAL MALFUNCTION THRESHOLDS
Monitor period of emission-related-misfire:
Monitor period of catalyst-damaged-misfire (MIL blinks):
FOR MEXICO MODELS:
Monitor period of emission-related-misfire: for Mexico models
Monitor period of catalyst-damaged-misfire (MIL blinks): for Mexico models
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 on (IG).
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 No. 1 to No. 8) with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.
8. Drive the vehicle several times with the conditions, such as engine speed and engine load, as shown in Misfire RPM and Misfire Load in the freeze frame data.
HINT
In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below with the engine speed and engine load the same as Misfire RPM and Misfire Load in the freeze frame data.
9. Check whether misfires have occurred by checking DTCs and freeze frame data.
HINT
Do not turn the ignition switch off until the stored DTCs and freeze frame data have been recorded. When the ECM returns to normal mode (default), the stored DTCs, freeze frame data and other data will be cleared.
10. Record the DTCs, freeze frame data and misfire counts.
11. Turn the ignition switch off and wait for at least 30 seconds.
12. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
INSPECTION PROCEDURE
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT
* If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
* Bank 1 refers to the bank that includes the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.
* Bank 2 refers to the bank that does not include the No. 1 cylinder.
* 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 volume in the tank.
(2) Improper fuel is used.
(3) 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 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 Reading and Clearing Diagnostic Trouble Codes.
(2) Start the engine and conduct the confirmation driving pattern.
(3) Read the misfiring rates of each cylinder or DTC(s) using the tester.
(4) Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.
(5) 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 misfire 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 DTCS OUTPUT (IN ADDITION TO MISFIRE CODES)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch on (IG).
(c) Turn the tester on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
HINT
Write down the DTCs.
Result:
HINT
If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305 and P0306 are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART SFI System
A -- Continue to next step.
2. CHECK PCV HOSE CONNECTIONS
(a) Check the PCV hose connection.
OK:
PCV hose is correctly connected and is not damaged.
NG -- REPAIR OR REPLACE PCV HOSE
OK -- Continue to next step.
3. READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch on (IG) and turn the tester on.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Misfire RPM and Misfire Load.
(d) 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.
4. READ VALUE USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch on (IG) and turn the tester on.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Catalyst OT MF F/C.
(d) Read the value displayed on the tester.
Result:
B -- READ VALUE USING TECHSTREAM
A -- Continue to next step.
5. PERFORM ACTIVE TEST USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch on (IG) and turn the tester on.
(c) Enter the following menus: Powertrain / Engine and ECT / Active Test / Prohibit the Catalyst OT Misfire prevent F/C.
(d) Perform the Active Test.
NOTICE:
When performing the Active Test, make sure the vehicle is stopped and either idling or being revved within 3000 rpm.
NEXT -- Continue to next step.
6. READ VALUE USING TECHSTREAM
(a) Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count, #2, #3, #4, #5 and #6
(b) Read each value for Cylinder #1 Misfire Count to #6 displayed on the tester. If no misfire counts occur in any cylinders, perform the following procedures:
Start the engine and let it idle.
Move the shift lever to the D position.
Check the Cylinder #1 Misfire Count to #6.
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 OF THE TECHSTREAM Misfire RPM AND Misfire Load)" procedures above.
(d) Read the Cylinder #1 Misfire Count to #6 or DTCs displayed on the tester.
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's record of the engine coolant temperature 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 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. CHECK SPARK PLUG
(a) Remove the ignition coil and the spark plug of the misfiring cylinder.
(b) Measure the spark plug electrode gap.
Maximum gap:
1.4 mm (0.0551 in.)
(c) Check the electrode for carbon deposits.
Recommended spark plug:
