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

MONITOR DESCRIPTION

If the difference between the requested MG2 torque and the actual MG2 torque exceeds a predetermined value, the MG ECU determines that there is a malfunction in the execution or monitoring of MG2 torque. Then, the power management control ECU will illuminate the MIL and set a DTC.

MONITOR STRATEGY

Related DTCs P0A78 (INF 306): Discrepancy between motor monitored torque and commanded torque
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 306) is not detected

CONFIRMATION DRIVING PATTERN

A011YEDE06

  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.

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

  6. Slowly accelerate from a stop (0 km/h (0 mph)) to 40 km/h (25 mph) several times while using different acceleration patterns.

    Tech Tips

    The vehicle should be driven with an accelerator opening of approximately 30%.

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

  8. Check that permanent DTCs are cleared.

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

Tech Tips

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

  • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

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

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

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.

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
      Only P0A78-306 is output or P0A78-306 and 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 power switch off.

    B

    GO TO DTC CHART (HYBRID CONTROL SYSTEM) Click here

    A

  2. 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
      Any of the following DTCs are also output. A
      Only P0A78-306 is output or P0A78-306 and 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 power switch off.

    B

    Click here

    A

  3. CHECK POWER MANAGEMENT CONTROL ECU

    1. Turn the power switch on (IG).

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

      A011VUSE04
      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A39-31 (HSDN) - I3-6 (E1) Power switch on (IG) Below 4.5 V
      Text in Illustration
      *a

      Component with harness connected

      (Power Management Control ECU)

    3. Turn the power switch off.

    NG

    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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. 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.

      A011XKAE01
      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 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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Remove the upper inverter cover (motor cable side) from the inverter with converter assembly.

      A011WHV

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

      A011XL5
      Specified Condition
      T=8.0 N*m (82 kgf*cm, 71 in.*lbf)

      Note

      Make sure that the tightening torque of the bolt is between 6.4 and 9.6 N*m (65 and 98 kgf*cm, 57 and 85 in.*lbf).

    4. Disconnect the motor cable from the inverter with converter assembly.

    5. Check for arc marks at the terminals for the motor cable.

      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 to the inverter with converter assembly.

    7. Install the upper inverter 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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Remove the upper inverter cover (generator cable side) and upper inverter cover (motor cable side) from the inverter with converter assembly.

      A011WF4

    3. Disconnect the generator cable and motor cable from the inverter with converter assembly.

      A011VFWE05
      Text in Illustration
      *1 Generator Cable
      *2 Motor Cable

    4. Check MG2 for an interphase short using a milliohmmeter.

      A011Z65E06

      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
        n1-1 (W) - n1-3 (U) Power switch off 71.4 to 81.0 mΩ
        n1-2 (V) - n1-1 (W) Power switch off 71.4 to 81.0 mΩ
        n1-3 (U) - n1-2 (V) Power switch off 74.4 to 84.1 mΩ
        Text in Illustration
        *1 Shield Ground
        *a

        Motor Cable

        (Inverter with Converter Assembly Side)

        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)

    5. 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
      n1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      n1-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      n1-3 (U) - Body ground and shield ground Power switch off 100 MΩ or higher

    6. Connect the generator cable and motor cable.

    7. Install the upper inverter cover (generator cable side) and upper inverter cover (motor cable side).

    NG

    Click here

    OK

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here

  7. CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR CABLE 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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

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

      A011X5E
      Specified Condition
      T=8.5 N*m (87 kgf*cm, 75 in.*lbf)

      Note

      Make sure that the tightening torque of the bolt is between 6.4 and 10.5 N*m (65 and 107 kgf*cm, 5 and 8 ft.*lbf).

    3. Disconnect the motor cable from the hybrid vehicle transaxle assembly.

    4. Check for arc marks at the terminals for the motor cable.

      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 to the hybrid vehicle transaxle assembly.

    B

    REPLACE MALFUNCTIONING PARTS

    C

    CONNECT SECURELY

    A

  8. CHECK MOTOR CABLE

    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. Remove the motor cable Click here.

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

      A011YPEE01

      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
      n1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      n1-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      n1-3 (U) - Body ground and shield ground Power switch off 100 MΩ or higher
      Text in Illustration
      *1 Shield ground
      *a

      Motor Cable

      (Inverter with Converter Assembly Side)
      *b

      Motor Cable

      (Hybrid Vehicle Transaxle Assembly Side)

      Note

      Wrap the terminal of the motor cable with insulating tape to prevent them 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
      n1-1 (W) - n2-3 (W) Power switch off Below 1 Ω
      n1-2 (V) - n2-2 (V) Power switch off Below 1 Ω
      n1-3 (U) - n2-1 (U) Power switch off Below 1 Ω
      n1-1 (W) - n2-1 (U) Power switch off 100 MΩ or higher
      n1-2 (V) - n2-3 (W) Power switch off 100 MΩ or higher
      n1-3 (U) - n2-2 (V) Power switch off 100 MΩ or higher

    5. Install the motor cable.

    NG

    REPLACE MOTOR CABLE Click here

    OK

    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY Click here

  9. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - 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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Disconnect connector A14 from the inverter with converter assembly.

    3. Disconnect connector A39 from the power management control ECU.

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

    5. Turn the power switch on (IG).

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

      A011WIWE02
      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A14-40 (HSDN) or A39-31 (HSDN) - Body ground Power switch on (IG) Below 1 V
      Text in Illustration
      *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 power switch on (IG) with the connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    7. Turn the power 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
      Tester Connection Switch Condition Specified Condition
      A39-31 (HSDN) - A39-1 (IG2) Power switch off 10 kΩ or higher
      A39-31 (HSDN) - A39-2 (IG2D) Power switch off 10 kΩ or higher
      A39-31 (HSDN) - A39-5 (+B1) Power switch off 10 kΩ or higher
      A39-31 (HSDN) - A39-6 (MREL) Power switch off 10 kΩ or higher
      A14-40 (HSDN) - A14-30 (+B) Power switch off 10 kΩ or higher
      A14-40 (HSDN) - A14-31 (+B2) Power 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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Disconnect connector A14 from the inverter with converter assembly.

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

      A011YPZE04
      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A14-40 (HSDN) - A14-30 (+B) Power switch off 5 kΩ or higher
      A14-40 (HSDN) - A14-31 (+B2) Power switch off 5 kΩ or higher
      Text in Illustration
      *a

      Component without harness connected

      (Inverter with Converter Assembly)

    4. Connect the inverter with converter assembly connector.

    NG

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here