HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-503

DTC Code DTC Name
P0A78-503 Drive Motor "A" Inverter Performance

DESCRIPTION

For a description of the inverter Click here.

If an overvoltage occurs in the motor inverter or generator inverter, the MG ECU detects it and transmits this information to the power management control ECU.

Tech Tips

The term "drive motor A" indicates MG2.

DTC No. INF Code DTC Detection Condition Trouble Area
P0A78 503 Motor inverter overvoltage signal detection (overvoltage due to MG ECU malfunction) Inverter with converter assembly

CAUTION / NOTICE / HINT

CAUTION:


  • Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, turn the ignition switch off and 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 ignition 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.

Tech Tips

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


  1. With the vehicle engine stopped, the ignition switch to ON (READY) and the shift lever in P, depress the accelerator pedal to start the engine.

PROCEDURE


  1. CHECK DTC OUTPUT (HYBRID CONTROL)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON (IG).

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

    4. Check if DTCs are output.

      Result
      Result Proceed to
      Only P0A78-503 is output, or DTCs other than the ones in the table below are also output. A
      Any of the following DTCs including pending DTCs are also output. B
      DTC No. Relevant Diagnosis
      P0A1A (all INF codes)*1 Generator Control Module
      P0A1B (all INF codes)*1 Drive Motor "A" Control Module
      P0A1D (all INF codes)*1 Hybrid Powertrain Control Module
      P0A3F-243 Drive Motor "A" Position Sensor Circuit
      P0A40-500 Drive Motor "A" Position Sensor Circuit Range / Performance
      P0A41-245 Drive Motor "A" Position Sensor Circuit Low
      P0A4B-253 Generator Position Sensor Circuit
      P0A4C-513 Generator Position Sensor Circuit Range / Performance
      P0A4D-255 Generator Position Sensor Circuit Low
      P0A60 (all INF codes)*1 Drive Motor "A" Phase V Current
      P0A63 (all INF codes)*1 Drive Motor "A" Phase W Current
      P0A72 (all INF codes)*1 Generator Phase V Current
      P0A75 (all INF codes)*1 Generator Phase W Current
      P0A78-266, 267, 287, 505, 506, 565, 586, 806, 807, 808 Drive Motor "A" Inverter Performance
      P0A7A-325, 517, 518, 809, 810, 811 Generator Inverter Performance
      P0A93-346 Inverter Cooling System Performance
      P0A94-554, 555, 556, 585, 587, 589, 590 DC / DC Converter Performance
      P0ADB-227 Hybrid Battery Positive Contactor Control Circuit Low
      P0ADC-226 Hybrid Battery Positive Contactor Control Circuit High
      P0ADF-229 Hybrid Battery Negative Contactor Control Circuit Low
      P0AE0-228 Hybrid Battery Negative Contactor Control Circuit High
      P0C73-776 Motor Electronics Coolant Pump "A" Control Performance
      P0C76-523 Hybrid battery System Discharge Time Too Long
      P3004-803 High Voltage Power Resource
      P314A-828 Inverter Coolant Pump Speed Signal

      Tech Tips


      • *1: If any INF codes are output for this DTC, refer to the corresponding diagnostic procedure.

      • P0A78-503 may be set due to a malfunction which also causes DTCs in the preceding table to be set. In this case, first troubleshoot the output DTCs in the preceding table. Then, perform a test to attempt to reproduce the problems, and check that no DTCs are output.

    5. Turn the ignition 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.

      Note

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

    2. A01UY1U

      Check the connector connections and contact pressure of the low voltage connectors of the inverter with converter assembly 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 connectors are connected securely and there are no contact pressure problems.

      Tech Tips

      When connecting the connector, insert it with the locking lever in the raised position. Rotate the lever downward and make sure that the connector is pulled into its socket. When the locking lever is in its fully closed position, a click will be heard as its locking claws engage. After the click is heard, pull up on the connector to confirm that it is properly connected.


    OK

    REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS Click here

    NG

    CONNECT SECURELY