HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A01-726, P0A04-725

DTC Code DTC Name
P0A01-726 Motor Electronics Coolant Temperature Sensor Circuit Range / Performance
P0A04-725 Motor Electronics Coolant Temperature Sensor Circuit Intermittent

DTC SUMMARY


  1. MALFUNCTION DESCRIPTION

    These DTCs indicate the temperature sensor value is abnormal. The cause of this malfunction may be one of the following:

    Area Main Malfunction Description Step
    Inverter low-voltage circuit The connectors are not connected properly 2
    EV cooling system Coolant circulation abnormal (frozen or leaking, etc.) 3
    Inside of inverter Inverter with converter assembly internal circuit malfunction 3

DESCRIPTION

The EV control ECU detects EV coolant temperature using the coolant temperature sensor built into the inverter with converter assembly. The EV control ECU uses signals from the coolant temperature sensor to check the effectiveness of the inverter cooling system. If necessary, the EV control ECU will limit inverter output to help prevent inverter overheating. The EV control ECU also detects malfunctions in the sensor based on the EV coolant temperature sensor values. The inverter with converter assembly detects malfunctions in the EV coolant temperature sensor and its wiring.

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate
P0A01-726 Motor Electronics Coolant Temperature Sensor Circuit Range / Performance

Abnormal deviation in inverter coolant temperature sensor output.

Both of the following conditions are met for 10 seconds or more:


  1. The difference between the estimated coolant (for inverter) temperature and the temperature sensor output is large.

  2. Coolant (for inverter) temperature is too high.

(1 trip detection logic)

  • Inverter cooling system

  • Cooling fan system

  • Inverter with converter assembly

  • Wire harness or connector

Master Warning Light:

Comes on
P0A04-725 Motor Electronics Coolant Temperature Sensor Circuit Intermittent

Sudden change in EV coolant temperature sensor output or hunting:

Unusual sudden change in EV coolant temperature sensor output occurs and the offset continues for a certain period of time.

Unusual sudden change in EV coolant temperature sensor output occurs repeatedly.

(1 trip detection logic)

  • Inverter cooling system

  • Cooling fan system

  • Inverter with converter assembly

  • Wire harness or connector

Master Warning Light:

Comes on

Note

Under extremely low temperatures, if the LLC freezes, DTC P0A01-726 may be detected.

Related Data List
DTC No. Data List
P0A01-726

  • Inverter Coolant Temperature

  • Ambient Temperature

  • Inverter Water Pump Revolution

  • Inverter Water Pump Run Control Duty
P0A04-725

CAUTION / NOTICE / HINT

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 assembly and EV battery.


    • 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 assembly and EV battery.

  • 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 assembly 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.

    Click here

    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


  • 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

  • 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).

Tech Tips

After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


  1. Turn the power switch on (READY) and wait for 90 seconds or more.

  2. Drive the vehicle for approximately 10 minutes referring to the following freeze frame data or Data List items: "Vehicle Speed".

PROCEDURE


  1. CHECK DTC OUTPUT (EV)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

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

    4. Check for DTCs.


      Powertrain > EV > Trouble Codes
      Result
      Result Proceed to
      P0A01-726 or P0A04-725 only is output, or DTCs except the ones in the table below are also output. A
      Any of the following DTCs are also output. B
      Relevant DTC
      P0A93-346 Inverter Cooling System Performance
      P0C73-776 Motor Electronics Coolant Pump "A" Control Performance
      P314A-828 Inverter Coolant Pump Speed Signal

      Tech Tips

      P0A01-726 or P0A04-725 may be output as a result of the malfunction indicated by the DTCs above.

    5. Turn the power switch off.


    B

    GO TO DTC CHART (HYBRID CONTROL SYSTEM) Click here

    A

  2. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR)

    CAUTION:

    Be sure to wear insulated gloves.


    1. Check that the service plug grip is not installed to FC stack assembly and EV battery.

      Note

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. A01MFWK

      Check the connection condition of the low voltage connector of the inverter with converter assembly and the contact pressure of each terminal. Check the terminals for deformation, and check the connector for water ingress and foreign matter.

      Click here

      Note

      Before disconnecting the connector, confirm that it is properly connected by checking that the locking claws are engaged and that the connector does not pull out.

      OK
      - The connector is connected securely.
      - The terminals are not deformed and are connected securely.
      - No water or foreign matter in the connector.
      Result
      Result Proceed to
      OK A
      NG (The connector is not connected securely.) B
      NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.) C

    B

    CONNECT SECURELY

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

  3. CHECK COOLING SYSTEM

    Click here

    Tech Tips

    If the "Cooling System" inspection results are normal, perform the next step.

    Result
    Proceed to
    NEXT

    NEXT

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here