Caution / Notice / Hint

HINT: 

• Check the "Fuel Cut Elps Time" in the Data List or the Freeze Frame Data.

  If the elapsed time is over 0 seconds, then the engine speed is high (engine speed at which fuel cut occurs + 500 rpm).

  When this has happened, there is the possibility that the No. 1 valve rocker arm sub-assembly will become loose and a fire could start, so check that the No. 1 valve rocker arm sub-assembly is properly attached.

  Refer to COMPONENTS [11/2021 - ]

• If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
• Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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 #8 Misfire Count).
• Be sure to confirm that no misfiring cylinder DTCs are stored again by performing the confirmation driving pattern after finishing repairs.
• For 8 cylinder engine, the ECM intentionally does not set the specific misfiring cylinder DTCs at high engine speed. If misfires occur only in high engine speed areas, only DTC P0300 is set.

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

  1. Clear the DTCs.

     Refer to DTC CHECK / CLEAR [11/2021 - ]

  2. Start the engine and conduct the confirmation driving pattern.
  3. Read the misfiring counts 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 set.
• When one of Short FT B1S1, Long FT B1S1, Short FT B2S1 or Long FT B2S1 in the freeze frame data is outside the range of +/-15%, the air fuel ratio may be rich (-15% or less) or lean (+15% or higher).
• When 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 to be stored.