Inspection Procedure

HINT: 

• 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
• 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 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 DTCs. Refer to DTC CHECK / CLEAR .
  2. Start the engine and conduct the confirmation driving pattern.
  3. Read the misfire count of each cylinder or DTC(s) using the Techstream.
  4. Repair the cylinder(s) that has a high misfiring count 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 to be detected.