HYBRID CONTROL SYSTEM Cooling System

DESCRIPTION

The cause of the malfunction may be the cooling system.

Check whether the grille is blocked, whether coolant is leaking, the HV radiator fan operating condition and whether coolant has frozen.

Related Parts Check
Area Inspection Step
Grille blockage, coolant amount, coolant hoses, HV radiator fan Check for overheating due to hybrid cooling system malfunction. 1, 2, 3, 4
Inverter coolant temperature sensor (built-in inverter) Check for temperature sensor malfunction. 5
Coolant freezing check Check freeze frame values to determine whether the hybrid coolant was frozen when the DTC was stored. 6

SYSTEM DESCRIPTION

The inverter converts the high-voltage direct current of the HV battery into alternating current for the generator (MG1) and motor (MG2). The inverter generates heat during the conversion process. Therefore, the inverter is cooled by a special cooling system consisting of the inverter water pump assembly, the cooling fan, and a radiator. This cooling system is independent of the engine cooling system. The power management control ECU monitors the inverter water pump assembly, cooling fan and cooling system, and detects malfunctions.

A01I382E01
Text in Illustration
*1 Inverter Water Pump Assembly *2 Inverter Reserve Tank Assembly
*3 Inverter with Converter Assembly *4 Radiator Assembly (HV)
*5 Hybrid Vehicle Transaxle Assembly - -

INSPECTION PROCEDURE

This step is referenced from the procedures for each DTC.

If the inspection results below are normal, perform the next procedure for the referenced DTC.

CAUTION:


  • Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. After removing the service plug grip, 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 Click here.

    Tech Tips

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

Note

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work Click here.

PROCEDURE


  1. CHECK VEHICLE CONDITION


    1. Make sure that the front side of the radiator grille is not blocked with anything.

    2. Ask the customer if the front side of the radiator grille was blocked with anything.

      Result
      Result Proceed to
      Not blocked. A
      Is/was blocked. B

      Tech Tips

      If the radiator grille is blocked, the inverter coolant temperature will increase and this DTC may be stored.


    B

    IF EQUIPPED, EXPLAIN TO CUSTOMER THAT OPTIONAL COVER WILL BE REMOVED

    A

  2. CHECK QUANTITY OF HV COOLANT


    1. Check the HV coolant level in the inverter reserve tank.

    2. Check for HV coolant leaks.

      Result
      Result Proceed to
      No leaks are found and coolant level in the inverter reserve tank assembly is above the low line. A
      No leaks are found and coolant level in the inverter reserve tank assembly is below the low line. B
      HV coolant leaks are evident. C

      Tech Tips

      After repairing the HV coolant leaks and adding coolant, perform the "Activate the Water Pump" Active Test (HV Active Test item) and the "Control the Electric Cooling Fan" Active Test (Engine Active Test item) and make sure that there are no malfunctions.


    B

    ADD HV COOLANT

    C

    INSPECT FOR HV COOLANT LEAK AND ADD HV COOLANT

    A

  3. CHECK COOLANT HOSE


    1. Check if the hoses of the cooling system are kinked or clogged.

      OK
      The cooling system hoses are not kinked or clogged.

    NG

    REPAIR OR REPLACE COOLANT HOSE

    OK

  4. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE ELECTRIC COOLING FAN)


    1. Connect the Techstream to the DLC3.

    2. Turn the power switch on (IG).

    3. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.

    4. Perform the "Control the Electric Cooling Fan" Active Test.

      OK
      The cooling fan rotates.

    5. Turn the power switch off.


    NG

    CHECK COOLING FAN SYSTEM Click here

    OK

  5. READ VALUE USING TECHSTREAM (DATA LIST)


    1. Turn the power switch off and leave the vehicle for at least 1 hour.

    2. Connect the Techstream to the DLC3.

    3. Turn the power switch on (IG).

    4. Enter the following menus: Powertrain / Hybrid Control / Data List / Inverter Coolant Water Temperature, Inverter Temp (MG2), Cnv Tmp (Upper), Cnv Temp (Lower), Inverter Temp (MG1).

    5. Read the Data List.

      Result
      Result Proceed to
      Other than below. A
      "Inverter Coolant Water Temperature" value is higher than the displayed temperature of any other Data List item by 20°C (36°F) or more. B

      Note

      The lower limit temperature that can be displayed for "Inverter Temp (MG1)", "Inverter Temp (MG2)", "Cnv Tmp (Upper)" and "Cnv Temp (Lower)" is 15°C (59°F). The lower limit temperature for "Inverter Coolant Water Temperature" is -40°C (-40°F). The "Inverter Coolant Water Temperature" value displayed on the Techstream may be lower than the others, but this is not a malfunction.

    6. Turn the power switch off.


    B

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here

    A

  6. CHECK HV COOLANT (CHECK FOR CONDITIONS THAT MAY HAVE CAUSED FREEZING)


    1. Connect the Techstream to the DLC3.

    2. Turn the power switch on (IG).

    3. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

    4. Read the freeze frame data Ambient Temperature using the Techstream.

    5. Check if the freeze frame data Ambient Temperature is below freezing.

      Result
      Result Proceed to
      Ambient Temperature value is above freezing temperature of the HV coolant. A
      Ambient Temperature value is below freezing temperature of the HV coolant. B

      Tech Tips


      • HV coolant (SLLC) with a 30% concentration freezes at -15 °C (5°F) and HV coolant (SLLC) with a 50% concentration freezes at -35°C (-31°F).

      • If the HV coolant freezes in the HV radiator or HV water pump, the coolant temperature in the inverter with converter assembly rises because the HV coolant cannot circulate. As a result, a DTC may be set.

      • A DTC is set when the water pump impeller cannot rotate due to freezing of the HV coolant.

      • If a DTC is set due to freezing of HV coolant, the problem cannot be reproduced. Judge whether freezing of HV coolant occurred according to the freeze point of the HV coolant, HV coolant change history and ambient temperature when the DTC was set.

    6. Turn the power switch off.


    B

    REPLACE HV COOLANT Click here

    A

    COOLING SYSTEM NORMAL (PERFORM NEXT STEP FOR REFERENCED DTC)