HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-284

DTC Code DTC Name
P0A78-284 Drive Motor "A" Inverter Performance

DESCRIPTION

For a description of the inverter, Click here.

If the motor inverter overheats, has a circuit malfunction, or has an internal short, the inverter transmits this information to the MG ECU via the motor inverter fail signal line.

DTC No. INF Code DTC Detection Condition Trouble Area
P0A78 284 Motor inverter fail signal detection (overheat)

  • Wire harness or connector

  • Inverter cooling system

  • No. 1 fan motor

  • Cooling fan ECU

  • Multiplex network front light ECU (Front controller)

  • Fusible link block assembly

  • Fuse

  • Water pump with motor and bracket assembly

  • Inverter with converter assembly

  • Hybrid vehicle control ECU

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.

Note

After troubleshooting and performing repairs for all output DTCs, be sure to replace the inverter with converter assembly.

Tech Tips

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

PROCEDURE


  1. 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
      P3246-202 is not output. A
      P3246-202 is output. B

    B

    GO TO DTC CHART Click here

    A

  2. 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
      P0A78-284 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, 279, 287, 306, 503, 504, 505, 506, 586, 806, 807, 808 Drive Motor "A" Inverter Performance
      P0A7A-325, 344, 517, 518, 809, 810, 811 Generator Inverter Performance
      P0A90-509 Drive Motor "A" Performance
      P0A92-521 Hybrid Generator Performance
      P0A94-442, 547, 548, 549, 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 flowchart.

      • P0A78-284 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. After troubleshooting and performing repairs for all output DTCs, be sure to replace the inverter with converter assembly.


    B

    GO TO DTC CHART Click here

    A

  3. CHECK QUANTITY OF HV COOLANT


    1. Check the coolant level in the inverter reserve tank.

      A01H01QE01

    2. Check for coolant leaks.

      Result
      Result Proceed to
      Coolant leaks are not evident. A sufficient amount of coolant remains in the inverter reserve tank. A
      Coolant leaks are not evident. No coolant remains in the inverter reserve tank. B
      Coolant leaks are evident. C

      Tech Tips

      After repairing the coolant leaks and adding coolant, perform the "Activate the Water Pump" active test (HV ECU active test item) and the "Control the Electric Cooling Fan" active test (Engine ECU active test item) and make sure that there are no malfunctions.


    B

    ADD HV COOLANT

    C

    CHECK FOR COOLANT LEAKS AND ADD COOLANT

    A

  4. CHECK COOLANT HOSE


    1. Check if the hoses of the cooling system are kinked or clogged.


    NG

    CORRECT THE PROBLEM

    OK

  5. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (WATER PUMP)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the following menu items: Powertrain / Hybrid Control / Active Test / Activate the Water Pump.

    4. Perform the "Activate the Water Pump" active test for at least 1 minute.

    5. Check that there are ripples in the coolant in the inverter reserve tank.

      A01H01QE01
      OK
      There are ripples in the coolant in the inverter reserve tank as long as the active test is being performed.

      Note

      In addition to the active test, the water pump with motor and bracket assembly will also operate with the power switch on (READY). However, the water pump with motor and bracket assembly will operate at low speed for 20 seconds after the power switch is turned on (READY).

      Tech Tips

      The water pump with motor and bracket assembly will also operate in inspection mode.


    NG

    Click here

    OK

  6. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (COOLING FAN)


    1. Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.

    2. Perform the "Control the Electric Cooling Fan" active test.

      OK
      The cooling fan rotates.

    NG

    CHECK COOLING FAN SYSTEM Click here

    OK

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

    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. 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.

      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.


    NG

    CONNECT SECURELY

    OK

  8. INSPECT COOLING SYSTEM (FOR CLOGGING)


    1. Drain the inverter coolant Click here.

      Note

      Do not reuse the drained coolant because it may contain foreign objects.

      Tech Tips

      Drain the inverter coolant with the inverter reserve tank cap installed.

    2. Install the inverter reserve tank cap.

    3. Remove the drain plug.

    4. A01H22SE01

      Disconnect end A of the No. 3 inverter cooling hose.

      Note


      • Applied air pressure should be 59 kPa (0.6 kgf/cm2, 8.6 psi) or less.

      • Be careful when disconnecting the hose. Coolant may spill out of the hose.

    5. A01H0T5E01

      Cover the pipe shown in the illustration with packing tape.

    6. Using an air gun, apply air to the disconnected end of the hose to check for clogging in the coolant path.

      Note

      Be careful when applying air. Applying excessive air may cause coolant to overflow from the inverter reserve tank cap.

      OK
      Coolant and air come out from the drain.
    7. A01H22SE01

      Connect end A of the No. 3 inverter cooling hose and disconnect end B.

    8. A01GYTSE01

      Cover the pipe shown in the illustration with packing tape.

    9. Using an air gun, apply air to the disconnected end of the hose to check for clogging in the coolant path.

      Note


      • Applied air pressure should be 59 kPa (0.6 kgf/cm2, 8.6 psi) or less.

      • Be careful when applying air. Applying excessive air may cause coolant to overflow from the inverter reserve tank cap.

      OK
      Coolant and air come out from the drain.
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    10. After this inspection, check for coolant leaks from the hose with the power switch on (READY).

      Note

      If leaks are found, replace the No. 3 inverter cooling hose and clamps.


    B

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here

    C

    REPLACE MALFUNCTIONING PARTS

    A

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here

  9. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (WATER PUMP)


    1. A01H19R

      Connect the intelligent tester to the DLC3.

    2. Compress the inlet hose for the water pump with motor and bracket assembly several times.

    3. Turn the power switch on (IG) again.

    4. Select the following menu items: Powertrain / Hybrid Control / Active Test / Activate the Water Pump.

    5. Perform the "Activate the Water Pump" active test for at least 1 minute.

    6. Check that there are ripples in the coolant in the inverter reserve tank.

      A01H01QE01
      OK
      There are ripples in the coolant in the inverter reserve tank as long as the active test is being performed.

      Note

      In addition to the active test, the water pump with motor and bracket assembly will also operate with the power switch on (READY). However, the water pump with motor and bracket assembly will operate at low speed for 20 seconds after the power switch is turned on (READY).

      Tech Tips

      The water pump with motor and bracket assembly will also operate in inspection mode.


    NG

    Click here

    OK

    ADD HV COOLANT

  10. CHECK FUSE (INV W/P)


    1. A01GYN7E01

      Check if there is an open circuit in the fuse (INV W/P) in the engine room No. 2 relay block.

      OK
      There is no open circuit in the fuse (INV W/P).

      Tech Tips

      If the result is NG, replace the fuse (INV W/P) with a new one.


    NG

    Click here

    OK

  11. CHECK CONNECTOR CONNECTION CONDITION (WATER PUMP WITH MOTOR AND BRACKET ASSEMBLY CONNECTOR)


    1. A01GZ88

      Check the connection of the water pump with motor and bracket assembly connector.

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

    NG

    CONNECT SECURELY

    OK

  12. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)


    1. Check the connections of the hybrid vehicle control ECU connectors.

      OK
      The connectors are connected securely and there are no contact problems.

    NG

    CONNECT SECURELY

    OK

  13. CHECK HARNESS AND CONNECTOR (WATER PUMP WITH MOTOR AND BRACKET ASSEMBLY)


    1. Disconnect connector A78 from the hybrid vehicle control ECU.

    2. Remove the fuse (INV W/P) from the engine room No. 2 relay block.

    3. Disconnect the water pump with motor and bracket assembly connector.

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

      A01H19IE04
      Standard resistance (Check for open)
      Tester Connection Switch Condition Specified Condition
      A78-23 (IWP) - zA1-2 (SWP) Power switch off Below 1 Ω
      zA1-3 (GND) - Body ground Power switch off Below 1 Ω
      Engine Room No. 2 Relay Block INV W/P Fuse Terminal 2 - zA1-4 (+BWP) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Switch Condition Specified Condition
      A78-23 (IWP) or zA1-2 (SWP) - Body ground and other terminals Power switch off 10 kΩ or higher
      Engine Room No. 2 Relay Block INV W/P Fuse Terminal 2 or zA1-4 (+BWP) - Body ground and other terminals Power switch off 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  14. CHECK WATER PUMP WITH MOTOR AND BRACKET ASSEMBLY


    1. A01GWJ8E01

      Apply 12 V to terminal 2 of the INV W/P fuse holder of the engine room No. 2 relay block and check that the water pump operates.

      OK
      The water pump operates.

    NG

    REPLACE WATER PUMP WITH MOTOR AND BRACKET ASSEMBLY Click here

    OK

    REPLACE HYBRID VEHICLE CONTROL ECU Click here

  15. CHECK CONNECTOR CONNECTION CONDITION (WATER PUMP WITH MOTOR AND BRACKET ASSEMBLY CONNECTOR)


    1. A01GZ88

      Check the connection of the water pump with motor and bracket assembly connector.

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

    NG

    CONNECT SECURELY

    OK

  16. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)


    1. Check the connections of the hybrid vehicle control ECU connectors.

      OK
      The connectors are connected securely and there are no contact problems.

    NG

    CONNECT SECURELY

    OK

  17. CHECK HARNESS AND CONNECTOR (WATER PUMP WITH MOTOR AND BRACKET ASSEMBLY)


    1. Disconnect connector A78 from the hybrid vehicle control ECU.

    2. Remove the fuse (INV W/P) from the engine room No. 2 relay block.

    3. Disconnect the water pump with motor and bracket assembly connector.

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

      A01H19IE04
      Standard resistance (Check for open)
      Tester Connection Switch Condition Specified Condition
      A78-23 (IWP) - zA1-2 (SWP) Power switch off Below 1 Ω
      zA1-3 (GND) - Body ground Power switch off Below 1 Ω
      Engine room No. 2 relay block INV W/P fuse terminal 2 - zA1-4 (+BWP) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Switch Condition Specified Condition
      A78-23 (IWP) or zA1-2 (SWP) - Body ground and other terminals Power switch off 10 kΩ or higher
      Engine room No. 2 relay block INV W/P fuse terminal 2 or zA1-4 (+BWP) - Body ground and other terminals Power switch off 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  18. CHECK WATER PUMP WITH MOTOR AND BRACKET ASSEMBLY


    1. A01GWJ8E01

      Apply 12 V to terminal 2 of the INV W/P fuse holder of the engine room No. 2 relay block and check that the water pump operates.

      OK
      The water pump operates.

    NG

    REPLACE WATER PUMP WITH MOTOR AND BRACKET ASSEMBLY Click here

    OK

    REPLACE HYBRID VEHICLE CONTROL ECU Click here