Caution / Notice / Hint

HINT: 

• If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
• FFVs update the alcohol concentration learned value (Alcohol Density Estimate) when the vehicle is refueled. As idling stability may decrease when fuels having different properties are used, check with the customer about the fuels recently used in the vehicle.
• Make sure to compare the value of "Alcohol Density Estimate" in the freeze frame data with the current "Alcohol Density Estimate" value in the Data List.
• 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 freeze frame data.
• If the misfire still cannot be reproduced even though the conditions stored in the freeze frame data have been duplicated, one of the following factors is considered to be a possible cause of the problem:
  1. The fuel level is low.
  2. Improper fuel is used.
  3. The spark plugs are dirty.
• After finishing repairs, check that no misfires occur in each cylinder (No. 1, No. 2, No. 3, No. 4, No. 5, No. 6, No. 7 and No. 8 cylinder).
• Be sure to confirm that no misfiring cylinder DTCs are stored again by conducting the confirmation driving pattern, after the repairs.
• For 6 and 8 cylinder engines, the ECM intentionally does not store the specific misfiring cylinder DTCs at high engine speeds. If misfires only occur during high engine speed driving, only DTC P0300 is stored.

  In the event of DTC P0300 being present, perform the following operations:

  1. Clear the DTC (Refer to DTC CHECK / CLEAR [08/2015 - 08/2018] ).
  2. Start the engine and conduct the confirmation driving pattern.
  3. Read the misfiring rates of each cylinder or DTC(s) using the Techstream.
  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 stored.
• With the alcohol concentration learned value, Long FT and Short FT in the freeze frame data, it is possible to determine the actual A/F deviation when a malfunction occurs.
• When the Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfires occurred only while warming up the engine.
• An extremely imbalanced drive wheel, which causes body vibration, may cause misfire DTCs detection.