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HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-503, P0A78-504

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DTC Code DTC Name
P0A78-503 Drive Motor "A" Inverter Performance
P0A78-504 Drive Motor "A" Inverter Performance
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DESCRIPTION

For a description of the inverter, (Click here).

If an overvoltage occurs in the motor inverter, the MG ECU detects it and transmits this information to the hybrid vehicle control ECU.

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

  • Wire harness or connector

  • Inverter with converter assembly

  • Hybrid vehicle transmission assembly
P0A78 504 Motor inverter overvoltage signal detection (overvoltage due to hybrid vehicle transmission assembly malfunction)
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WIRING DIAGRAM

Refer to the wiring diagrams for DTC P0A1A-200 (Click here).

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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 disconnecting 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.

Tip:

Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

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PROCEDURE


  1. Click here

    CHECK DTC OUTPUT (HV)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.

    4. Check if DTCs are output.

      Result
      Result Proceed to
      P0A78-503 or P0A78-504 only is output. A
      Any of the following 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, 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
      P0AE0-228 Hybrid Battery Negative Contactor Control Circuit High
      P0C76-523 Hybrid Battery System Discharge Time Too Long
      Tip:

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

      • P0A78-503 or P0A78-504 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.


  2. Click here

    CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR)

    CAUTION:

    Be sure to wear insulated gloves.

    Note:

    Before disconnecting the connector, confirm that it is properly connected by checking that the locking claws are engaged and that the connector cannot be pulled out.


    1. Turn the power switch off.

    2. Remove the service plug grip (Click here).

      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.

    3. Check the connection of the low voltage connector of the inverter with converter assembly.

      OK
      The connector is connected securely and there are no contact problems.
      Tip:

      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.


  3. Click here

    CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - GENERATOR RESOLVER)


    1. A01H1UUE04

      Disconnect the low voltage connector from the inverter with converter assembly.

    2. Turn the power switch on (IG).

    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-20 (GRF) - Body ground Power switch on (IG) Below 1 V
      A79-9 (GRFG) - Body ground Power switch on (IG) Below 1 V
      A79-18 (GSN) - Body ground Power switch on (IG) Below 1 V
      A79-7 (GSNG) - Body ground Power switch on (IG) Below 1 V
      A79-17 (GCS) - Body ground Power switch on (IG) Below 1 V
      A79-6 (GCSG) - Body ground Power switch on (IG) Below 1 V
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-20 (GRF) - Body ground Power switch on (IG) Below 1 V
      A88-9 (GRFG) - Body ground Power switch on (IG) Below 1 V
      A88-18 (GSN) - Body ground Power switch on (IG) Below 1 V
      A88-7 (GSNG) - Body ground Power switch on (IG) Below 1 V
      A88-17 (GCS) - Body ground Power switch on (IG) Below 1 V
      A88-6 (GCSG) - Body ground Power switch on (IG) Below 1 V
      Note:

      Turning the power switch on (IG) with the low voltage connector of the inverter with converter assembly disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.


  4. Click here

    CHECK GENERATOR RESOLVER


    1. A01H1UUE04

      Turn the power switch off.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open)
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-20 (GRF) - A79-9 (GRFG) Power switch off 4.2 to 12.5 Ω
      A79-18 (GSN) - A79-7 (GSNG) Power switch off 9.8 to 20.1 Ω
      A79-17 (GCS) - A79-6 (GCSG) Power switch off 9.8 to 20.1 Ω
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-20 (GRF) - A88-9 (GRFG) Power switch off 4.2 to 12.5 Ω
      A88-18 (GSN) - A88-7 (GSNG) Power switch off 9.8 to 20.1 Ω
      A88-17 (GCS) - A88-6 (GCSG) Power switch off 9.8 to 20.1 Ω
      Standard resistance (Check for short)
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-20 (GRF) or A79-9 (GRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-18 (GSN) or A79-7 (GSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-17 (GCS) or A79-6 (GCSG) - Body ground and other terminals Power switch off 1 MΩ or higher
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-20 (GRF) or A88-9 (GRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-18 (GSN) or A88-7 (GSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-17 (GCS) or A88-6 (GCSG) - Body ground and other terminals Power switch off 1 MΩ or higher

  5. Click here

    CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - MOTOR RESOLVER)


    1. Turn the power switch on (IG).

    2. A01H1UUE03

      Measure the voltage according to the value(s) in the table below.

      Standard voltage
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-40 (MRF) - Body ground Power switch on (IG) Below 1 V
      A79-29 (MRFG) - Body ground Power switch on (IG) Below 1 V
      A79-39 (MSN) - Body ground Power switch on (IG) Below 1 V
      A79-28 (MSNG) - Body ground Power switch on (IG) Below 1 V
      A79-38 (MCS) - Body ground Power switch on (IG) Below 1 V
      A79-27 (MCSG) - Body ground Power switch on (IG) Below 1 V
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-40 (MRF) - Body ground Power switch on (IG) Below 1 V
      A88-29 (MRFG) - Body ground Power switch on (IG) Below 1 V
      A88-39 (MSN) - Body ground Power switch on (IG) Below 1 V
      A88-28 (MSNG) - Body ground Power switch on (IG) Below 1 V
      A88-38 (MCS) - Body ground Power switch on (IG) Below 1 V
      A88-27 (MCSG) - Body ground Power switch on (IG) Below 1 V
      Note:

      Turning the power switch on (IG) with the low voltage connector of the inverter with converter assembly disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.


  6. Click here

    CHECK MOTOR RESOLVER


    1. Turn the power switch off.

    2. A01H1UUE03

      Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open)
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-40 (MRF) - A79-29 (MRFG) Power switch off 4.5 to 16.8 Ω
      A79-39 (MSN) - A79-28 (MSNG) Power switch off 9.3 to 27.8 Ω
      A79-38 (MCS) - A79-27 (MCSG) Power switch off 12.4 to 30.7 Ω
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-40 (MRF) - A88-29 (MRFG) Power switch off 4.5 to 16.8 Ω
      A88-39 (MSN) - A88-28 (MSNG) Power switch off 9.3 to 27.8 Ω
      A88-38 (MCS) - A88-27 (MCSG) Power switch off 12.4 to 30.7 Ω
      Standard resistance (Check for short)
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-40 (MRF) or A79-29 (MRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-39 (MSN) or A79-28 (MSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-38 (MCS) or A79-27 (MCSG) - Body ground and other terminals Power switch off 1 MΩ or higher
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-40 (MRF) or A88-29 (MRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-39 (MSN) or A88-28 (MSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-38 (MCS) or A88-27 (MCSG) - Body ground and other terminals Power switch off 1 MΩ or higher

  7. Click here

    CHECK CONNECTOR CONNECTION CONDITION (GENERATOR RESOLVER CONNECTOR)


    1. Check the connection of the generator resolver connector.

      OK
      The connector is connected securely and there are no contact problems.

  8. Click here

    CHECK CONNECTOR CONNECTION CONDITION (MOTOR RESOLVER CONNECTOR)


    1. Check the connection of the motor resolver connector.

      OK
      The connector is connected securely and there are no contact problems.
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

  9. Click here

    CHECK CONNECTOR CONNECTION CONDITION (GENERATOR RESOLVER CONNECTOR)


    1. Check the connection of the generator resolver connector.

      OK
      The connector is connected securely and there are no contact problems.

  10. Click here

    CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - GENERATOR RESOLVER)


    1. A01GWIOE03

      Disconnect the generator resolver connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open)
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-20 (GRF) - E62-1 (GRF) Power switch off Below 1 Ω
      A79-9 (GRFG) - E62-5 (GRFG) Power switch off Below 1 Ω
      A79-18 (GSN) - E62-2 (GSN) Power switch off Below 1 Ω
      A79-7 (GSNG) - E62-6 (GSNG) Power switch off Below 1 Ω
      A79-17 (GCS) - E62-3 (GCS) Power switch off Below 1 Ω
      A79-6 (GCSG) - E62-7 (GCSG) Power switch off Below 1 Ω
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-20 (GRF) - E62-1 (GRF) Power switch off Below 1 Ω
      A88-9 (GRFG) - E62-5 (GRFG) Power switch off Below 1 Ω
      A88-18 (GSN) - E62-2 (GSN) Power switch off Below 1 Ω
      A88-7 (GSNG) - E62-6 (GSNG) Power switch off Below 1 Ω
      A88-17 (GCS) - E62-3 (GCS) Power switch off Below 1 Ω
      A88-6 (GCSG) - E62-7 (GCSG) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-20 (GRF) or E62-1 (GRF) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-9 (GRFG) or E62-5 (GRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-18 (GSN) or E62-2 (GSN) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-7 (GSNG) or E62-6 (GSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-17 (GCS) or E62-3 (GCS) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-6 (GCSG) or E62-7 (GCSG) - Body ground and other terminals Power switch off 1 MΩ or higher
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-20 (GRF) or E62-1 (GRF) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-9 (GRFG) or E62-5 (GRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-18 (GSN) or E62-2 (GSN) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-7 (GSNG) or E62-6 (GSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-17 (GCS) or E62-3 (GCS) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-6 (GCSG) or E62-7 (GCSG) - Body ground and other terminals Power switch off 1 MΩ or higher
      Tip:

      The generator resolver is not available separately. If it requires replacement, replace the hybrid vehicle transmission assembly.


  11. Click here

    CHECK CONNECTOR CONNECTION CONDITION (MOTOR RESOLVER CONNECTOR)


    1. Check the connection of the motor resolver connector.

      OK
      The connector is connected securely and there are no contact problems.

  12. Click here

    CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - MOTOR RESOLVER)


    1. A01GWIOE04

      Disconnect the motor resolver connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open)
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-40 (MRF) - E63-1 (MRF) Power switch off Below 1 Ω
      A79-29 (MRFG) - E63-5 (MRFG) Power switch off Below 1 Ω
      A79-39 (MSN) - E63-2 (MSN) Power switch off Below 1 Ω
      A79-28 (MSNG) - E63-6 (MSNG) Power switch off Below 1 Ω
      A79-38 (MCS) - E63-3 (MCS) Power switch off Below 1 Ω
      A79-27 (MCSG) - E63-7 (MCSG) Power switch off Below 1 Ω
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-40 (MRF) - E63-1 (MRF) Power switch off Below 1 Ω
      A88-29 (MRFG) - E63-5 (MRFG) Power switch off Below 1 Ω
      A88-39 (MSN) - E63-2 (MSN) Power switch off Below 1 Ω
      A88-28 (MSNG) - E63-6 (MSNG) Power switch off Below 1 Ω
      A88-38 (MCS) - E63-3 (MCS) Power switch off Below 1 Ω
      A88-27 (MCSG) - E63-7 (MCSG) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      LHD
      Tester Connection Switch Condition Specified Condition
      A79-40 (MRF) or E63-1 (MRF) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-29 (MRFG) or E63-5 (MRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-39 (MSN) or E63-2 (MSN) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-28 (MSNG) or E63-6 (MSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-38 (MCS) or E63-3 (MCS) - Body ground and other terminals Power switch off 1 MΩ or higher
      A79-27 (MCSG) or E63-7 (MCSG) - Body ground and other terminals Power switch off 1 MΩ or higher
      RHD
      Tester Connection Switch Condition Specified Condition
      A88-40 (MRF) or E63-1 (MRF) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-29 (MRFG) or E63-5 (MRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-39 (MSN) or E63-2 (MSN) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-28 (MSNG) or E63-6 (MSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-38 (MCS) or E63-3 (MCS) - Body ground and other terminals Power switch off 1 MΩ or higher
      A88-27 (MCSG) or E63-7 (MCSG) - Body ground and other terminals Power switch off 1 MΩ or higher
      Tip:

      The motor resolver is not available separately. If it requires replacement, replace the hybrid vehicle transmission assembly.


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    GO TO DTC CHARTClick here

  14. Click here

    CONNECT SECURELY

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    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLYClick here

  16. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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    REPLACE INVERTER WITH CONVERTER ASSEMBLYClick here

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    REPLACE INVERTER WITH CONVERTER ASSEMBLYClick here