HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A01-726 and 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

    Inverter low-voltage circuit

    The connectors are not connected properly

    2

    Hybrid cooling system

    Coolant circulation abnormal (frozen or leaking, etc.)

    3

    Inside of inverter

    Inside of inverter

    Inverter with converter assembly internal circuit malfunction

    3

DESCRIPTION

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

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

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

Comes on

Master Warning Light:

Comes on

P0A04-725

Motor Electronics Coolant Temperature Sensor Circuit Intermittent

Sudden change in HV coolant temperature sensor output or hunting:

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

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

(1 trip detection logic)

  • Inverter cooling system

  • Cooling fan system

  • Inverter with converter assembly

  • Wire harness or connector

Comes on

Master Warning Light:

Comes on
Table 1. Related Data List

DTC No.

ECU Data List

P0A01-726

  • Inverter Coolant Water Temperature

  • Ambient Temperature

  • (Inverter) W/P Run Control Duty

  • Inverter W/P Revolution

P0A04-725

CAUTION / NOTICE / HINT

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

    Tip:

    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 hereClick hereClick hereClick here

Tip:

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 Spd".

PROCEDURE

  1. CHECK DTC OUTPUT (HYBRID CONTROL)

    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

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

    4. Check for DTCs.

      Powertrain > Hybrid Control > 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
      Tip:

      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 hereClick hereClick here

    A

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

    Click here

    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

    Tip:

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

    Result

    Proceed to

    NEXT
    NEXT

    REPLACE INVERTER WITH CONVERTER ASSEMBLY

    Click here