Inspection Procedure

HINT: 

• If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
• Read freeze frame data using 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. Refer to DTC CHECK / CLEAR .
  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 unbalanced drive wheel which causes body vibration may cause misfire DTCs to be detected.

• An extremely unbalanced drive wheel which causes body vibration may cause misfire DTCs to be detected.