Lexus ES: Inverter "A" Cooling System Performance (P0A9300)

• Inverter internal circuit malfunction
• Malfunction in ECU that controls the inverter
• Malfunction in sensor for inverter control (coolant temperature sensor)

• Coolant is leaking, insufficient coolant level, frozen or the passenger of coolant is clogged.
• Grille is blocked.

HINT:

• After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

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• When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

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1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG) and turn the Techstream on.
3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
4. Turn the power switch off and wait for 2 minutes or more.
5. Turn the power switch on (IG) and turn the Techstream on.
6. With power switch on (IG) and wait for 5 seconds or more. [*1]
7. Turn the power switch on (READY) and wait for 5 seconds or more. [*2]
8. Perform a road test according to the freeze frame data item "Vehicle Speed" for approximately 10 minutes. [*3]

   NOTICE:

   As the state of charge of the HV battery voltage may be low after driving in fail-safe mode, it will automatically be charged for 5 to 10 minutes after repairs have been performed and turn the power switch on (READY).

   HINT:

   [*1] to [*3] : Normal judgment procedure.

   The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

9. Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.
10. Check the DTC judgment result.

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE or N/A, perform the normal judgment procedure again.

CAUTION:

• Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grip from HV battery.
  • Inspecting the high-voltage system
  • Disconnecting the low voltage connector of the inverter with converter assembly
  • Disconnecting the low voltage connector of the HV battery
• To prevent electric shock, make sure to remove the service plug grip to cut off the high voltage circuit before servicing the vehicle.
• After removing the service plug grip from the HV battery, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
• After removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.

  *a	Without waiting for 10 minutes

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  HINT:

  Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

HINT:

• P0A9300 may be output as a result of the malfunction indicated by the DTCs above.
  1. The chart above is listed in inspection order of priority.
  2. Check DTCs that are output at the same time by following the listed order. (The main cause of the malfunction can be determined without performing unnecessary inspections.)

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