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.

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A DTC is stored when the actual motor torque deviates from the torque requested by the MG ECU to motor (MG2).

Tech Tips

The term "drive motor A" indicates motor (MG2).

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Warning Indicate
P0A78-306 Drive Motor "A" Inverter Performance

Motor (MG2) torque execution monitoring malfunction

The difference between the motor torque requested by the power management ECU and actual motor torque is large.

(1 trip detection logic)

  • Hybrid vehicle transmission assembly

  • Motor cable

  • Inverter with converter assembly

 Comes on

Master Warning Light:

Comes on
Related Data List
DTC No. Data List
P0A78-306

  • Motor(MG2) Torq

  • M(MG2) Trq Exec Val

  • Vehicle Spd

WIRING DIAGRAM

Refer to the wiring diagram for DTC P0AA6-526.

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Refer to the wiring diagram for DTC P321E-318.

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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

    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

Tech Tips

After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


  1. Turn the power switch 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 power switch on (IG).

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

    4. Check for DTCs.


      Powertrain > Hybrid Control > Trouble Codes
      Result
      Result Proceed to
      P0A78-306 only is output, or DTCs except the ones in the table below are also output. A
      Any of the following DTCs are also output. B
      Relevant DTC
      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 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.


    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 power switch on (IG).

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

    4. Check for DTCs.


      Powertrain > Hybrid Control > Trouble Codes
      Result
      Result Proceed to
      Any of the following DTCs are also output. A
      P0A78-306 only is output, or DTCs except the ones in the table below are also output. B
      Relevant DTC
      P0A7A-344 Generator Inverter Performance
      P0A92-261, 521 Hybrid Generator Performance

      Tech Tips

      When the DTCs listed in the preceding table 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

    GO TO STEP 4 Click here

    A

  3. CHECK POWER MANAGEMENT CONTROL ECU

    Result
    Proceed to
    OK
    NG

    1. Disconnect the A62 power management control ECU connector.

    2. B003Y98C03
      *a

      Component without harness connected

      (Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A62-34 (HTM+) - A62-33 (HTM-) Power switch off 80 to 162 Ω
      A62-21 (MTH+) - A62-20 (MTH-) Power switch off 80 to 162 Ω
      A62-32 (REQ+) - A62-31 (REQ-) Power switch off 80 to 162 Ω
      A62-29 (CLK+) - A62-28 (CLK-) Power switch off 80 to 162 Ω

    3. Reconnect the A62 power management control ECU connector.

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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

    Result
    Result Proceed to
    OK A
    NG (The connector is not connected securely.) B
    NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.) C

    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 connection condition of the low voltage connector of the inverter with converter assembly and the contact pressure of each terminal. Check the terminals for deformation, and check the connector for water ingress and foreign matter.

      Click here

      A0020YPC01
      *A for LHD *B for RHD

      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 connector is connected securely.
      - The terminals are not deformed and are connected securely.
      - No water or foreign matter in the connector.
      Result
      Result Proceed to
      OK A
      NG (The connector is not connected securely.) B
      NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.) C

      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.


    B

    CONNECT SECURELY

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

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

    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

    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. B003XQMC01
      *A for LHD
      *B for RHD

      for Type A:


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

    3. B003XRQC01
      *A for LHD
      *B for RHD

      for Type B:


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

    4. B003YDNC01
      *A for LHD
      *B for RHD
      *1

      Motor Cable

      (Inverter with Converter Assembly Side)

      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.

      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).

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

    6. 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

    7. Connect the motor cable to the inverter with converter assembly.

    8. Install the inverter cover.


    B

    REPLACE MALFUNCTIONING PARTS

    C

    CONNECT SECURELY

    A

  6. CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (MG2)

    Result
    Proceed to
    OK
    NG

    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. B003XQMC01
      *A for LHD
      *B for RHD

      for Type A:


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

    3. B003XRQC01
      *A for LHD
      *B for RHD

      for Type B:


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

    4. B003YFOC01
      *A for LHD
      *B for RHD
      *1

      Motor Cable

      (Inverter with Converter Assembly Side)
      *2

      Generator Cable

      (Inverter with Converter Assembly Side)

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

    5. B003XT1C01
      *A for LHD
      *B for RHD
      *1 Shield Ground
      *a

      Motor Cable

      (Inverter with Converter Assembly Side)

      Check motor (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 motor (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
        for LHD
        Tester Connection Condition Specified Condition
        m3-3 (W) - m3-1 (U) Power switch off 47.0 to 51.8 mΩ
        m3-2 (V) - m3-3 (W) Power switch off 47.3 to 52.1 mΩ
        m3-1 (U) - m3-2 (V) Power switch off 47.1 to 51.9 mΩ
        for RHD
        Tester Connection Condition Specified Condition
        m1-1 (W) - m1-3 (U) Power switch off 47.0 to 51.8 mΩ
        m1-2 (V) - m1-1 (W) Power switch off 47.3 to 52.1 mΩ
        m1-3 (U) - m1-2 (V) Power switch off 47.1 to 51.9 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. When checking for a short circuit between motor phases without using a milliohmmeter.

      Note

      The motor generates current when wheels are rotated by hand. Before performing the inspection, wrap the motor cable terminals with insulation tape.

      Tech Tips

      A short circuit between the motor phases can be checked simply without using a milliohmmeter.


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

      2. Turn the power switch on (IG).

        Note

        Turning the power switch on (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.

      3. Move the shift lever to N.

      4. Lift up the vehicle.

      5. Rotate the rear wheels in the same direction simultaneously by hand.

        Standard
        Left and right wheels rotate smoothly (No short circuit between phases)

        Tech Tips

        If a short circuit exists between the motor phases, the rear wheels do not rotate smoothly (some resistance is felt).

      6. Move the shift lever to P.

      7. Lower the vehicle.

      8. Turn the power switch off.

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

    7. 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
      for LHD
      Tester Connection Condition Specified Condition
      m3-3 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      m3-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      m3-1 (U) - Body ground and shield ground Power switch off 100 MΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      m1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      m1-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      m1-3 (U) - Body ground and shield ground Power switch off 100 MΩ or higher

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

      Tech Tips

      Perform this procedure only when checking for a short circuit between motor phases without using a milliohmmeter.

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      m3-3(W) - m3-2(V) Power switch off Below 1 Ω
      m3-2(V) - m3-1(U) Power switch off Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      m1-1(W) - m1-2(V) Power switch off Below 1 Ω
      m1-2(V) - m1-3(U) Power switch off Below 1 Ω

    9. Connect the generator cable and motor cable.

    10. Install the inverter cover.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here

    NG

  7. CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (MOTOR CABLE CONNECTION CONDITION)

    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

    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 hybrid vehicle transmission assembly.

      Click here

    3. B003Y69

      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.

      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 hybrid vehicle transmission 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 hybrid vehicle transmission assembly.

    7. Install the hybrid vehicle transmission assembly.


    B

    REPLACE MALFUNCTIONING PARTS

    C

    CONNECT SECURELY

    A

  8. CHECK MOTOR CABLE

    Result
    Proceed to
    OK
    NG

    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.

      B003Y7WC02
      *A for LHD *B for RHD
      *1 Shield ground - -
      *a

      Motor Cable

      (Inverter with Converter Assembly Side)

      		 *b

      Motor Cable

      (Hybrid Vehicle Transmission Assembly Side)

      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
      for LHD
      Tester Connection Condition Specified Condition
      m3-3 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      m3-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      m3-1 (U) - Body ground and shield ground Power switch off 100 MΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      m1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      m1-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      m1-3 (U) - Body ground and shield ground Power switch off 100 MΩ or higher

      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
      for LHD
      Tester Connection Condition Specified Condition
      m3-3 (W) - m2-3 (U) Power switch off 100 MΩ or higher
      m3-2 (V) - m2-1 (W) Power switch off 100 MΩ or higher
      m3-1 (U) - m2-2 (V) Power switch off 100 MΩ or higher
      m3-3 (W) - m2-1 (W) Power switch off Below 1 Ω
      m3-2 (V) - m2-2 (V) Power switch off Below 1 Ω
      m3-1 (U) - m2-3 (U) Power switch off Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      m1-1 (W) - m2-3 (U) Power switch off 100 MΩ or higher
      m1-2 (V) - m2-1 (W) Power switch off 100 MΩ or higher
      m1-3 (U) - m2-2 (V) Power switch off 100 MΩ or higher
      m1-1 (W) - m2-1 (W) Power switch off Below 1 Ω
      m1-2 (V) - m2-2 (V) Power switch off Below 1 Ω
      m1-3 (U) - m2-3 (U) Power switch off Below 1 Ω

    5. Install the motor cable.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here

    NG

    REPLACE MOTOR CABLE Click here

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

    Result
    Proceed to
    OK
    NG

    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 A62 power management control ECU connector.

    3. Disconnect the A28*1 or A29*2 inverter with converter assembly connector.


      • *1: for LHD

      • *2: for RHD

    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.

      B003YH9C04
      *A for LHD *B for RHD
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      		 *b

      Front view of wire harness connector

      (to Inverter with Converter Assembly)
      Standard Voltage
      for LHD
      Tester Connection Condition Specified Condition
      A62-30 (HSDN) or A28-25 (HSDN) - Body ground Power switch on (IG) Below 1 V
      for RHD
      Tester Connection Condition Specified Condition
      A62-30 (HSDN) or A29-25 (HSDN) - Body ground Power switch on (IG) Below 1 V

      Note

      Turning the power switch on (IG) with the power management control ECU and inverter with converter assembly 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
      for LHD
      Tester Connection Condition Specified Condition
      A62-30 (HSDN) - A62-1 (+B2) Power switch off 10 kΩ or higher
      A62-30 (HSDN) - A62-4 (MREL) Power switch off 10 kΩ or higher
      A29-25 (HSDN) - A29-10 (+B) Power switch off 10 kΩ or higher
      A29-25 (HSDN) - A29-11 (+B2) Power switch off 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      A62-30 (HSDN) - A62-1 (+B2) Power switch off 10 kΩ or higher
      A62-30 (HSDN) - A62-4 (MREL) Power switch off 10 kΩ or higher
      A29-25 (HSDN) - A29-10 (+B) Power switch off 10 kΩ or higher
      A29-25 (HSDN) - A29-11 (+B2) Power switch off 10 kΩ or higher

    10. Reconnect the A28*1 or A29*2 inverter with converter assembly connector.


      • *1: for LHD

      • *2: for RHD

    11. Reconnect the A62 power management control ECU connector.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK INVERTER WITH CONVERTER ASSEMBLY

    Result
    Proceed to
    OK
    NG

    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 A28*1 or A29*2 inverter with converter assembly connector.


      • *1: for LHD

      • *2: for RHD

    3. B003XOKC20
      *A for LHD
      *B for RHD
      *a

      Component without harness connected

      (Inverter with Converter Assembly)

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A28-25 (HSDN) - A28-10 (+B) Power switch off 5 kΩ or higher
      A28-25 (HSDN) - A28-11 (+B2) Power switch off 5 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      A29-25 (HSDN) - A29-10 (+B) Power switch off 5 kΩ or higher
      A29-25 (HSDN) - A29-11 (+B2) Power switch off 5 kΩ or higher

    4. Reconnect the A28*1 or A29*2 inverter with converter assembly connector.


      • *1: for LHD

      • *2: for RHD

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    NG

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here