FC BOOST 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 EV radiator fan operating condition and whether EV coolant has frozen.

Related Parts Check
Area Inspection Step
Grille blockage, coolant amount, coolant hoses, EV radiator fan Check for overheating due to EV cooling system malfunction 1, 2, 3, 4
FC boost control ECU check Inspect ECU estimated temperature abnormality 5
Coolant freezing check Check freeze frame values to determine whether the EV coolant was frozen when the DTC was stored 6

SYSTEM DESCRIPTION

The inverter inside the PCU and the auxiliary pump inverter generate heat in the process of converting high voltage DC from the EV battery to AC for the motor/FC air compressor or FC water pump/hydrogen pump. Also, the FC converter generates heat in the process of boosting the voltage from the FC stack and supplying it to the PCU. For this reason, each inverter and the FC converter are cooled by a dedicated cooling system incorporating the EV water pump with motor assembly, EV radiator fan, and radiator assembly (HV). This cooling system is independent from the FC stack cooling system. The EV control ECU monitors the EV water pump with motor assembly, EV radiator fan, and cooling system and detects malfunctions.

B000ZGYC02
*1 EV Water Pump with Motor Assembly *2 Inverter Reserve Tank Assembly
*3 Inverter with Converter Assembly *4 Radiator Assembly (HV)
*5 FCV Transaxle with Motor Assembly *6 FC Converter Assembly

CAUTION / NOTICE / HINT

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:


  • B006JFB
    B006JM4

    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 grips from both FC stack and EV battery assemblies.


    • Inspecting the high-voltage system

    • Disconnecting the low voltage connector of the inverter with converter assembly

    • Disconnecting the low voltage connector of the EV battery

    • Disconnecting the low voltage connector of the FC stack assembly

    • Disconnecting the low voltage connector of the FC converter assembly

      Tech Tips

      No removal order is specified for the service plug grips of the FC stack and EV battery assemblies.

  • B006JBZ

    After removing the service plug grip from the EV 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 grip from the FC stack assembly, store it in a safe location and use the "HIGH-VOLTAGE, DO NOT TOUCH" sign to notify other technicians that you are working on the high-voltage system.

  • B000ZMTC04
    *a Without waiting for 10 minutes

    After removal of the service plug grips of both FC stack and EV battery, wait for at least 10 minutes before touching the high-voltage connectors and 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.

    Tech Tips

    At least 10 minutes are necessary to discharge the high-voltage capacitors inside the inverter with converter assembly and FC stack assembly.

Note


  • When reinstalling the service plug grip to the FC stack assembly or the EV battery, slide the lever of the service plug until the letters "UNLOCK" are completely hidden, and insert it firmly.

    Click here

  • When the vehicle is parked with the power switch off, if the FC control ECU judges that the FC stack temperature will go below 0°C (32°F), it activates the FC air compressor, hydrogen pump and FC cooling water pump for a maximum of 180 seconds and drains water from the FC stack assembly. When performing inspection or repairs with the power switch off (not on (IG) or on (READY)), disconnect the cable from the negative (-) auxiliary battery terminal before performing work (If the auxiliary battery voltage is needed to conduct inspection, warm up the FC system beforehand).

  • 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 COMPONENTS WILL BE REMOVED

    A

  2. CHECK QUANTITY OF EV COOLANT


    1. Check that the inverter reserve tank assembly contains coolant at the Low level or higher.

    2. Check for EV coolant leaks.

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

      Tech Tips


      • After repairing the EV coolant leaks and adding coolant, perform the "Activate the Water Pump" Active Test (EV Active Test item) and the "Radiator Fan1", "Radiator Fan2" Active Test (FC Active Test item) and make sure that there are no malfunctions.

      • The EV water pump with motor assembly has a protection circuit function in case of water leakage, so it does not need to be replaced unless the cause of the water leak is the EV water pump with motor assembly itself.


    B

    ADD HV COOLANT

    C

    INSPECT FOR COOLANT LEAK AND ADD COOLANT

    A

  3. CHECK COOLANT HOSE


    1. Check that the cooling system hoses are not kinked or clogged.

      OK
      The cooling system hoses are not kinked or clogged.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE COOLANT HOSE

    OK

  4. PERFORM ACTIVE TEST USING GTS (RADIATOR FAN1, RADIATOR FAN2)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / FC / Active Test / Radiator Fan1, Radiator Fan2


      Powertrain > FC > Active Test
      Tester Display
      Radiator Fan1

      Powertrain > FC > Active Test
      Tester Display
      Radiator Fan2

    5. Perform the Active Test.

      OK
      The cooling fan rotates.
      Result
      Proceed to
      OK
      NG

    6. Turn the power switch off.


    NG

    CHECK COOLING FAN SYSTEM Click here

    OK

  5. READ VALUE USING GTS


    1. Turn the power switch off and wait for 1 hour or more.

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Turn the GTS on.

    5. Enter the following menus: Powertrain / EV / Data List / Inverter Coolant Temperature


      Powertrain > EV > Data List
      Tester Display
      Inverter Coolant Temperature

    6. Enter the following menus: Powertrain / FCDC / Data List / FC Converter Estimated Water Temperature (U/V/W/X Total), U Phase FC Converter Estimated Water Temperature, V Phase FC Converter Estimated Water Temperature, W Phase FC Converter Estimated Water Temperature, X Phase FC Converter Estimated Water Temperature


      Powertrain > FCDC > Data List
      Tester Display
      FC Converter Estimated Water Temperature (U/V/W/X Total)
      U Phase FC Converter Estimated Water Temperature
      V Phase FC Converter Estimated Water Temperature
      W Phase FC Converter Estimated Water Temperature
      X Phase FC Converter Estimated Water Temperature

    7. Read the Data List.

      Result
      Result Proceed to
      Difference between temperature displays of Data List (FCDC) items "FC Converter Estimated Water Temperature (U/V/W/X Total), U Phase FC Converter Estimated Water Temperature, V Phase FC Converter Estimated Water Temperature, W Phase FC Converter Estimated Water Temperature and X Phase FC Converter Estimated Water Temperature" and the Data List (EV) item "Inverter Coolant Temperature" is less than 20°C. A
      Difference between temperature displays of Data List (FCDC) items "FC Converter Estimated Water Temperature (U/V/W/X Total), U Phase FC Converter Estimated Water Temperature, V Phase FC Converter Estimated Water Temperature, W Phase FC Converter Estimated Water Temperature and X Phase FC Converter Estimated Water Temperature" and the Data List (EV) item "Inverter Coolant Temperature" is 20°C or greater. B

      Tech Tips

      Data List (FCDC) and Data List (EV) can be checked simultaneously using the Data List functions of the GTS.

    8. Turn the power switch off.


    B

    REPLACE FC CONVERTER ASSEMBLY Click here

    A

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


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / EV / Trouble Codes.


      Powertrain > EV > Trouble Codes

    5. Read the freeze frame data item "Ambient Temperature" using the GTS.

    6. Check if the freeze frame data item "Ambient Temperature" is below the freezing temperature of the HV coolant.

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

      Tech Tips


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

      • If the EV coolant freezes, the EV coolant will not be able to circulate, so the coolant temperature inside the FC converter assembly will increase, which may result in DTC output.

      • A DTC is stored when the EV water pump with motor assembly impeller cannot rotate due to freezing of the HV coolant.

      • If DTCs are output due to freezing of the EV coolant, the problem symptom cannot be reproduced. Check the EV coolant replacement history and whether the EV coolant was frozen based on the ambient temperature when the DTCs were stored.

    7. Turn the power switch off.


    A

    OTHERS COOLING SYSTEM NORMAL (PERFORM NEXT STEP FOR REFERENCED DTC)

    B

    REPLACE EV COOLANT Click here