Caution / Notice / Hint

WARNING: This page is about a different car, the 2024 Lexus TX 550h+. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Inspect the fuses for circuits related to this system before performing the following procedure.
Vehicle Control History may be stored in the hybrid vehicle control ECU assembly if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the freeze frame data and Vehicle Control History can be useful for troubleshooting.
Refer to VEHICLE CONTROL HISTORY (RoB) [12/2023 - ]

(Select Powertrain in Health Check and then check the time stamp data.)
If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU assembly, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.
Refer to VEHICLE CONTROL HISTORY (RoB) [12/2023 - ]

HINT:

If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
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 (Misfire Count Cylinder #1 to Misfire Count Cylinder #6).
Be sure to confirm that no misfiring cylinder DTCs are stored again by performing the confirmation driving pattern after finishing repairs.
For 6 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 P0300-00 is set.
In the event of DTC P0300-00 being present, perform the following operations:
1. Clear the DTCs.
  Refer to DTC CHECK / CLEAR [12/2023 - ]
2. Put the engine in Inspection Mode (2WD for measuring Exhaust Gas).
  Refer to INSPECTION MODE PROCEDURE [09/2023 - ]
3. Start the engine and conduct the confirmation driving pattern.
4. Read the misfiring counts of each cylinder or DTC(s) using the GTS.
5. Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.
6. After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300-00 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 +/-20%, the air fuel ratio may be rich (-20% or less) or lean (+20% or higher).
When Coolant Temperature 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.