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HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-504

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Info Added 2017-08-02

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DTC Code DTC Name
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 or generator inverter, the MG ECU detects it and transmits this information to the power management control ECU.

Tip:

The term "drive motor A" indicates MG2.

DTC No. INF Code DTC Detection Condition Trouble Area
P0A78 504 Motor inverter overvoltage signal detection (overvoltage due to hybrid vehicle transaxle assembly malfunction)

  • Inverter with converter assembly

  • Hybrid vehicle transaxle assembly

  • Wire harness or connector
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WIRING DIAGRAM

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

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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 here).

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PROCEDURE


  1. Click here

    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.

      Result
      Result Proceed to
      P0A78-504 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
      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
      Tip:

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

      • P0A78-504 may be stored due to a malfunction which also causes DTCs in the preceding table to be stored. 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 power switch off.


  2. Click here

    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. A00046KE03

      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.
      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)

    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. Disconnect the D3 inverter with converter assembly connector.

    3. Connect the cable to the negative (-) auxiliary battery terminal.

    4. Turn the power switch on (IG).

    5. B001VF3E02

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      D3-1 (GRF) - Body ground Power switch on (IG) Below 1 V
      D3-7 (GRFG) - Body ground Power switch on (IG) Below 1 V
      D3-2 (GSN) - Body ground Power switch on (IG) Below 1 V
      D3-8 (GSNG) - Body ground Power switch on (IG) Below 1 V
      D3-3 (GCS) - Body ground Power switch on (IG) Below 1 V
      D3-9 (GCSG) - Body ground Power switch on (IG) Below 1 V
      Table 1. Text in Illustration
      *a

      Front view of wire harness connector

      (to Inverter with Converter Assembly)
      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. Turn the power switch off.

    7. Disconnect the cable from the negative (-) auxiliary battery terminal.

    8. Reconnect the D3 inverter with converter assembly connector.


    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  4. Click here

    CHECK GENERATOR RESOLVER

    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. Disconnect the D3 inverter with converter assembly connector.

    3. B001VF3E02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D3-1 (GRF) - D3-7 (GRFG) Power switch off 4.2 to 12.5 Ω
      D3-2 (GSN) - D3-8 (GSNG) Power switch off 9.8 to 20.1 Ω
      D3-3 (GCS) - D3-9 (GCSG) Power switch off 9.8 to 20.1 Ω
      Tip:

      To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 20°C (68°F).

      R20 = Rt / {1 + 0.00393 X (T - 20)}

      The calculation is based on the following:

      R20: Resistance at 20°C (68°F) (mΩ)

      Rt: Measured resistance (mΩ)

      T: Temperature when the resistance is measured (°C (°F).)

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D3-1 (GRF) or D3-7 (GRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      D3-2 (GSN) or D3-8 (GSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      D3-3 (GCS) or D3-9 (GCSG) - Body ground and other terminals Power switch off 1 MΩ or higher
      Table 2. Text in Illustration
      *a

      Front view of wire harness connector

      (to Inverter with Converter Assembly)

    4. Reconnect the D3 inverter with converter assembly connector.


  5. Click here

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

    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. Disconnect the D3 inverter with converter assembly connector.

    3. Connect the cable to the negative (-) auxiliary battery terminal.

    4. Turn the power switch on (IG).

    5. B001VCME02

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      D3-4 (MRF) - Body ground Power switch on (IG) Below 1 V
      D3-11 (MRFG) - Body ground Power switch on (IG) Below 1 V
      D3-5 (MSN) - Body ground Power switch on (IG) Below 1 V
      D3-12 (MSNG) - Body ground Power switch on (IG) Below 1 V
      D3-6 (MCS) - Body ground Power switch on (IG) Below 1 V
      D3-13 (MCSG) - Body ground Power switch on (IG) Below 1 V
      Table 3. Text in Illustration
      *a

      Front view of wire harness connector

      (to Inverter with Converter Assembly)
      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. Turn the power switch off.

    7. Disconnect the cable from the negative (-) auxiliary battery terminal.

    8. Reconnect the D3 inverter with converter assembly connector.


    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. Click here

    CHECK MOTOR RESOLVER

    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. Disconnect the D3 inverter with converter assembly connector.

    3. B001VCME02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D3-4 (MRF) - D3-11 (MRFG) Power switch off 4.2 to 12.5 Ω
      D3-5 (MSN) - D3-12 (MSNG) Power switch off 9.8 to 20.1 Ω
      D3-6 (MCS) - D3-13 (MCSG) Power switch off 9.8 to 20.1 Ω
      Tip:

      To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 20°C (68°F).

      R20 = Rt / {1 + 0.00393 X (T - 20)}

      The calculation is based on the following:

      R20: Resistance at 20°C (68°F) (mΩ)

      Rt: Measured resistance (mΩ)

      T: Temperature when the resistance is measured (°C (°F).)

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D3-4 (MRF) or D3-11 (MRFG) - Body ground and other terminals Power switch off 1 MΩ or higher
      D3-5 (MSN) or D3-12 (MSNG) - Body ground and other terminals Power switch off 1 MΩ or higher
      D3-6 (MCS) or D3-13 (MCSG) - Body ground and other terminals Power switch off 1 MΩ or higher
      Table 4. Text in Illustration
      *a

      Front view of wire harness connector

      (to Inverter with Converter Assembly)

    4. Reconnect the D3 inverter with converter assembly connector.


  7. Click here

    CHECK CONNECTOR CONNECTION CONDITION (GENERATOR RESOLVER CONNECTOR)


    1. B001VD0

      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. B001VHU

      Check the connection of the motor resolver connector.

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

    • OK

      REPLACE INVERTER WITH CONVERTER ASSEMBLY (Click here)

    • NG

      CONNECT SECURELY

  9. Click here

    CHECK CONNECTOR CONNECTION CONDITION (GENERATOR RESOLVER CONNECTOR)


    1. B001VD0

      Check the connection of the generator resolver connector.

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

  10. Click here

    INSPECT HYBRID VEHICLE TRANSAXLE ASSEMBLY (GENERATOR RESOLVER)


    1. B001VD0E08

      Disconnect the D12 generator resolver connector.

    2. B001VHYC01
      *a

      Component without harness connected

      (Generator Resolver (Hybrid Vehicle Transaxle Assembly))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D12-1 (GRF) - D12-6 (GRFG) Power switch off 5.8 to 11.8 Ω
      D12-2 (GSN) - D12-7 (GSNG) Power switch off 11.7 to 17.7 Ω
      D12-3 (GCS) - D12-8 (GCSG) Power switch off 11.7 to 17.7 Ω
      Tip:

      To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 20°C (68°F).

      R20 = Rt / {1 + 0.00393 X (T - 20)}

      The calculation is based on the following:

      R20: Resistance at 20°C (68°F) (mΩ)

      Rt: Measured resistance (mΩ)

      T: Temperature when the resistance is measured (°C (°F).)

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D12-1 (GRF) - Body ground and other terminals (except 6 (GRFG)) Power switch off 1 MΩ or higher
      D12-6 (GRFG) - Body ground and other terminals (except 1 (GRF)) Power switch off 1 MΩ or higher
      D12-2 (GSN) - Body ground and other terminals (except 7 (GSNG)) Power switch off 1 MΩ or higher
      D12-7 (GSNG) - Body ground and other terminals (except 2 (GSN)) Power switch off 1 MΩ or higher
      D12-3 (GCS) - Body ground and other terminals (except 8 (GCSG)) Power switch off 1 MΩ or higher
      D12-8 (GCSG) - Body ground and other terminals (except 3 (GCS)) Power switch off 1 MΩ or higher
      Tip:

      The generator resolver is not available as a supply part. If it requires replacement, replace the hybrid vehicle transaxle assembly.

    3. Reconnect the D12 generator resolver connector.


    • OK

      REPAIR OR REPLACE HARNESS OR CONNECTOR

    • NG

      REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY (Click here)

  11. Click here

    CHECK CONNECTOR CONNECTION CONDITION (MOTOR RESOLVER CONNECTOR)


    1. B001VHU

      Check the connection of the motor resolver connector.

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

  12. Click here

    INSPECT HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR RESOLVER)


    1. B001VHUE03

      Disconnect the D11 motor resolver connector.

    2. B001VC9C05
      *a

      Component without harness connected

      (Motor Resolver (Hybrid Vehicle Transaxle Assembly))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D11-1 (MRF) - D11-4 (MRFG) Power switch off 5.8 to 11.8 Ω
      D11-2 (MSN) - D11-5 (MSNG) Power switch off 11.7 to 17.7 Ω
      D11-3 (MCS) - D11-6 (MCSG) Power switch off 11.7 to 17.7 Ω
      Tip:

      To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 20°C (68°F).

      R20 = Rt / {1 + 0.00393 X (T - 20)}

      The calculation is based on the following:

      R20: Resistance at 20°C (68°F) (mΩ)

      Rt: Measured resistance (mΩ)

      T: Temperature when the resistance is measured (°C (°F).)

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D11-1 (MRF) - Body ground and other terminals (except 4 (MRFG)) Power switch off 1 MΩ or higher
      D11-4 (MRFG) - Body ground and other terminals (except 1 (MRF)) Power switch off 1 MΩ or higher
      D11-2 (MSN) - Body ground and other terminals (except 5 (MSNG)) Power switch off 1 MΩ or higher
      D11-5 (MSNG) - Body ground and other terminals (except 2 (MSN)) Power switch off 1 MΩ or higher
      D11-3 (MCS) - Body ground and other terminals (except 6 (MCSG)) Power switch off 1 MΩ or higher
      D11-6 (MCSG) - Body ground and other terminals (except 3 (MCS)) Power switch off 1 MΩ or higher
      Tip:

      The motor resolver is not available as a supply part. If it requires replacement, replace the hybrid vehicle transaxle assembly.

    3. Reconnect the D11 motor resolver connector.


    • OK

      REPAIR OR REPLACE HARNESS OR CONNECTOR

    • NG

      REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY (Click here)