HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-306

DTC Code DTC Name
P0A78-306 Drive Motor "A" Inverter Performance

DESCRIPTION

For a description of the inverter Click here.

If the MG2 torque execution value does not correspond to the torque command value from the MG ECU to MG2, the power management control ECU will store this DTC.

Tech Tips

The term "drive motor A" indicates MG2.

DTC No. INF Code DTC Detection Condition Trouble Area
P0A78 306 MG2 torque execution monitoring malfunction

  • Hybrid vehicle transaxle assembly

  • Motor cable

  • Inverter with converter assembly

WIRING DIAGRAM

Refer to the wiring diagram for DTC P0AA6-526 Click here.

Refer to the wiring diagram for DTC P321E-318 Click here.

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. Turn the ignition switch to ON (READY) and wait for 5 seconds or more.

  2. Perform a road test according to the freeze frame data and item "Vehicle Spd" for approximately 10 minutes.

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 P0A78-306 is output, or DTCs other than the ones in the table below are also 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
      P0A78-202, 266, 267, 279, 287, 503, 504, 505, 506, 586, 806, 807, 808 Drive Motor "A" Inverter Performance
      P0A7A-203, 325, 517, 518, 809, 810, 811 Generator Inverter Performance
      P0A94-547, 548, 549, 554, 555, 556, 585, 587, 589, 590 DC / DC Converter Performance
      P0AA6 (all INF codes)*1 Hybrid Battery Voltage System Isolation Fault
      P0C76-523 Hybrid Battery System Discharge Time Too Long
      P3004-132 High Voltage Power Resource

      Tech Tips


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

      • P0A78-306 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 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
      Any of the following DTCs are also output. A
      Only P0A78-306 is output, or DTCs other than the ones in the table below are also output. B
      DTC No. Relevant Diagnosis
      P0A7A-344 Generator Inverter Performance
      P0A92-261, 521 Hybrid Generator Performance

      Tech Tips

      When the DTCs listed in the table above are also output, there may be a short between the HSDN (MG shut down signal) circuit and power circuit.

    5. Turn the ignition switch off.


    B

    CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR) Click here

    A

  3. CHECK POWER MANAGEMENT CONTROL ECU


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

    2. A01UXM9E02
      Text in Illustration
      *a

      Component with harness connected

      (Power Management Control ECU)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A27-31 (HSDN) - F55-6 (E1) Ignition switch ON (IG) Below 4.5 V

    3. Turn the ignition switch off.


    NG

    CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - POWER MANAGEMENT CONTROL ECU) Click here

    OK

  4. 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.


    NG

    CONNECT SECURELY

    OK

  5. CHECK INVERTER WITH CONVERTER ASSEMBLY (MOTOR CABLE (FOR MG2) CONNECTION CONDITION)

    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. A01UZ06

      Remove the inverter terminal cover from the inverter with converter assembly.

    3. A01UY3HE03

      Check that the bolts for the motor cable (for MG2) are tightened to the specified torque, the motor cable (for MG2) is connected securely, and there are no contact problems.

      Specified Condition
      Bolt A
      T=8.0 N*m (82 kgf*cm, 71 in.*lbf)
      Bolt B
      T=9.2 N*m (94 kgf*cm, 81 ft.*lbf)

      Note

      Make sure that the tightening torque of the bolt B is between 6.4 and 12 N*m (65 and 122 kgf*cm, 57 and 106 in.*lbf).

    4. Disconnect the motor cable (for MG2) from the inverter with converter assembly.

    5. Check for arc marks at the terminals for the motor cable (for MG2).

      Result
      Result Proceed to
      The terminals are connected securely and there are no contact problems. There are no arc marks. A
      The terminals are not connected securely and there is a contact problem. There are arc marks. B
      The terminals are not connected securely and there is a contact problem. There are no arc marks. C
      The terminals are connected securely and there are no contact problems. There are arc marks. B

    6. Connect the motor cable (for MG2) to the inverter with converter assembly.

    7. Install the inverter terminal cover.


    B

    REPLACE MALFUNCTIONING PARTS

    C

    CONNECT SECURELY

    A

  6. CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MG2)

    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. A01UZ06

      Remove the inverter terminal cover from the inverter with converter assembly.

    3. A01UXQS

      Remove the inverter cover from the inverter with converter assembly.

    4. A01V1DV

      Disconnect the motor cable from the inverter with converter assembly.

    5. A01V0VSE01
      Text in Illustration
      *1 Shield Ground
      *a

      Motor Cable (for MG2)

      (Inverter with Converter Assembly Side)

      Check MG2 for an interphase short using a milliohmmeter.


      1. Using a milliohmmeter, measure the resistance according to the value(s) in the table below.

        Tech Tips

        If the MG2 temperature is high, the resistance will vary greatly from the specification. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

        Standard Resistance
        Tester Connection Switch Condition Specified Condition
        W4-1 (W) - W4-2 (U) Ignition switch off 172.5 to 190.7 mΩ
        W4-2 (U) - W4-3 (V) Ignition switch off 172.5 to 190.7 mΩ
        W4-3 (V) - W4-1 (W) Ignition switch off 172.5 to 190.7 mΩ

        Tech Tips

        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)

    6. Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.

      Note

      Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      W4-1 (W) - Body ground and shield ground Ignition switch off 100 MΩ or higher
      W4-2 (U) - Body ground and shield ground Ignition switch off 100 MΩ or higher
      W4-3 (V) - Body ground and shield ground Ignition switch off 100 MΩ or higher

    7. Connect the motor cable.

    8. Install the inverter cover.

    9. Install the inverter terminal cover.


    OK

    REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS Click here

    NG

  7. CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR CABLE (FOR MG2) CONNECTION CONDITION)

    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. A01UZNOE03

      Check that the bolts for the motor cable (for MG2) are tightened to the specified torque, the motor cable (for MG2) is connected securely, and there are no contact problems.

      Specified Condition
      Bolt A
      T=19.5 N*m (199 kgf*cm, 14 ft.*lbf)
      Bolt B
      T=10 N*m (102 kgf*cm, 7 ft.*lbf)

      Note


      • Make sure that the tightening torque of the bolt A is between 13.5 and 25 N*m (138 and 255 kgf*cm, 10 and 18 ft.*lbf).

      • Make sure that the tightening torque of the bolt B is between 8 and 12 N*m (82 and 122 kgf*cm, 71 and 106 in.*lbf).

    3. Disconnect the motor cable (for MG2) from the hybrid vehicle transaxle assembly.

    4. Check for arc marks at the terminals for the motor cable (for MG2).

      Result
      Result Proceed to
      The terminals are connected securely and there are no contact problems. There are no arc marks. A
      The terminals are not connected securely and there is a contact problem. There are arc marks. B
      The terminals are not connected securely and there is a contact problem. There are no arc marks. C
      The terminals are connected securely and there are no contact problems. There are arc marks. B

    5. Connect the motor cable (for MG2) to the hybrid vehicle transaxle assembly.


    B

    REPLACE MALFUNCTIONING PARTS

    C

    CONNECT SECURELY

    A

  8. CHECK MOTOR CABLE (FOR MG2)

    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. Remove the motor cable Click here.

    3. A01UYRDE01
      Text in Illustration
      *1 Shield Ground
      *a

      Motor Cable (for MG2)

      (Inverter with Converter Assembly Side)
      *b

      Motor Cable (for MG2)

      (Hybrid Vehicle Transaxle Assembly Side)

      Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.

      Note

      Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      W4-1 (W) - Body ground and shield ground Ignition switch off 100 MΩ or higher
      W4-2 (U) - Body ground and shield ground Ignition switch off 100 MΩ or higher
      W4-3 (V) - Body ground and shield ground Ignition switch off 100 MΩ or higher

      Note

      Wrap the connector W3 terminal of the motor cable (for MG2) with insulating tape to prevent it from coming into contact with body ground

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      W4-1 (W) - W3-1 (W) Ignition switch off Below 1 Ω
      W4-2 (U) - W3-3 (U) Ignition switch off Below 1 Ω
      W4-3 (V) - W3-2 (V) Ignition switch off Below 1 Ω
      W4-1 (W) - W3-3 (U) Ignition switch off 100 MΩ or higher
      W4-2 (U) - W3-2 (V) Ignition switch off 100 MΩ or higher
      W4-3 (V) - W3-1 (W) Ignition switch off 100 MΩ or higher

    5. Install the motor cable.


    OK

    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY Click here

    NG

    REPLACE MOTOR CABLE Click here

  9. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - POWER MANAGEMENT CONTROL ECU)

    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. Disconnect the inverter with converter assembly connector.

    3. Disconnect the power management control ECU connector.

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

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

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

      A01UZIAE03
      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A33-31 (HSDN) or A27-31 (HSDN) - Body ground Ignition switch ON (IG) Below 1 V
      Text in Illustration
      *A w/ Power Switch
      *a

      Front view of wire harness connector

      (to Inverter with Converter Assembly)
      *b

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Note

      Turning the ignition switch to ON (IG) with the connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    7. Turn the ignition switch off.

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

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

      Standard Resistance (w/ Power Switch)
      Tester Connection Switch Condition Specified Condition
      A27-31 (HSDN) - A27-1 (IG2) Power switch off 10 kΩ or higher
      A27-31 (HSDN) - A27-2 (IG2D) Power switch off 10 kΩ or higher
      A27-31 (HSDN) - A27-5 (+B1) Power switch off 10 kΩ or higher
      A27-31 (HSDN) - A27-6 (MREL) Power switch off 10 kΩ or higher
      A33-31 (HSDN) - A33-10 (+B) Power switch off 10 kΩ or higher
      A33-31 (HSDN) - A33-9 (+B2) Power switch off 10 kΩ or higher
      Standard Resistance (w/o Power Switch)
      Tester Connection Switch Condition Specified Condition
      A27-31 (HSDN) - A27-1 (IG2) Ignition switch off 10 kΩ or higher
      A27-31 (HSDN) - A27-5 (+B1) Ignition switch off 10 kΩ or higher
      A27-31 (HSDN) - A27-6 (MREL) Ignition switch off 10 kΩ or higher
      A33-31 (HSDN) - A33-10 (+B) Ignition switch off 10 kΩ or higher
      A33-31 (HSDN) - A33-9 (+B2) Ignition switch off 10 kΩ or higher

    10. Connect the inverter with converter assembly connector.

    11. Connect the power management control ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK INVERTER WITH CONVERTER ASSEMBLY

    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. Disconnect the inverter with converter assembly connector.

    3. A01UZTCE01
      Text in Illustration
      *a

      Component without harness connected

      (Inverter with Converter Assembly)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A33-31 (HSDN) - A33-10 (+B) Ignition switch off 5 kΩ or higher
      A33-31 (HSDN) - A33-9 (+B2) Ignition switch off 5 kΩ or higher

    4. Connect the inverter with converter assembly connector.


    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    NG

    REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS Click here