HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-503

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

DTC SUMMARY

MALFUNCTION DESCRIPTION

These DTCs indicate that an overvoltage in the inverter has occurred. The cause of this malfunction may be one of the following:


  1. Internal inverter malfunction:


    • Inverter internal circuit malfunction

    • Malfunction in ECU that controls the inverter

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 motor (MG2).

DTC No. INF Code DTC Detection Condition Trouble Area
P0A78 503

Motor inverter overvoltage signal detected (overvoltage due to MG ECU malfunction):

Overvoltage is detected after boosting.*

(1 trip detection logic)

 Inverter with converter assembly

Related Data List
DTC No. Data List
P0A78-503 VH-Voltage after Boosting

MONITOR DESCRIPTION

If the motor inverter detects overvoltage, it will transmit an overvoltage signal to the MG ECU. Upon receiving this signal, the power management control ECU will illuminate the MIL and set a DTC.

MONITOR STRATEGY

Related DTCs P0A78 (INF 503): OVH detection (Over voltage malfunction)
Required sensors / components Motor inverter
Frequency of operation Continuous
Duration TMC's intellectual property
MIL operation 1 driving cycle
Sequence of operation None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not present TMC's intellectual property
Other conditions belong to TMC's intellectual property -

TYPICAL MALFUNCTION THRESHOLDS

TMC's intellectual property -

COMPONENT OPERATING RANGE

Power management control ECU DTC P0A78 (INF 503) is not detected

CONFIRMATION DRIVING PATTERN

A01I36OE01

  1. Connect the Techstream to the DLC3.

  2. Turn the power switch on (IG) and turn the Techstream on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the power switch off and wait for 30 seconds or more.

  5. Turn the power switch on (IG) and turn the Techstream on.

  6. Turn the power switch on (READY).

  7. With the shift lever in P, and engine stopped, depress the accelerator pedal to start the engine. [A]

  8. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes. [B]

  9. Read the current DTCs.

    Tech Tips


    • If a current DTC is output, the system is malfunctioning.

    • If a current DTC is not output and want to confirm permanent DTC, perform the following procedure.

  10. Check that permanent DTCs are cleared.

  11. If the permanent DTCs are not cleared, perform a universal trip, and then check for permanent DTCs again.

INSPECTION PROCEDURE

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.

Tech Tips

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


  1. With the engine stopped, the power switch 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 Techstream to the DLC3.

    2. Turn the power switch on (IG).

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

    4. Check if DTCs are output.

      Result
      Result Proceed to
      P0A78-503 only is output, or DTCs except the ones in the table below are also output. A
      Any of the following DTCs including pending DTCs are also output. B
      Malfunction Content Relevant DTC
      Microcomputer malfunction P0A1A (all INF codes)*1 Generator Control Module
      P0A1B-168, 192, 193, 198, 661, 786, 794, 795, 796 Drive Motor "A" Control Module
      P0A1D (all INF codes)*1 Hybrid Powertrain Control Module
      Power source circuit malfunction P0A1B-163, 164, 511, 512 Drive Motor "A" Control Module
      Sensor and actuator circuit malfunction 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
      P0A93-346 Inverter Cooling System Performance
      P0C73-776 Motor Electronics Coolant Pump "A" Control Performance
      P314A-828 Inverter Coolant Pump Speed Signal
      System malfunction 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
      P3004-803 High Voltage Power Resource
      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
      P0A94-554, 555, 556, 585, 587, 589, 590 DC / DC Converter Performance
      P0C76-523 Hybrid battery System Discharge Time Too Long

      Tech Tips


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

      • P0A78-503 may be output as a result of the malfunction indicated by the DTCs above.


        1. The chart above is listed in inspection order of priority.

        2. Check DTCs that are output at the same time by following the listed order. (The main cause of the malfunction can be determined without performing unnecessary inspections.)

    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.

      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. 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.

      A01I3MYE01
      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

      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.


    B

    CONNECT SECURELY

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here