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Home >> Scion >> 2014 >> iQ EV >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Testing and Diagnosis >> Hybrid Control System (Diagnostic Codes P0516-769 - P0A90-251) (Electric) >> Hybrid Control System >> DTC P0A78-202: Drive Motor "A" Inverter Performance >> Procedure

DTC P0A78-202: Drive Motor "A" Inverter Performance: Procedure

  1. CHECK EV TRANSAXLE WITH MOTOR ASSEMBLY See step   7 

    NG → See step   4 

    OK: Go to next step 

  2. REPLACE INVERTER WITH CONVERTER ASSEMBLY 

    Refer to COMPONENTS

    NEXT: Go to next step 

  3. CHECK DTC OUTPUT (EV) 
    1. Check the other DTCs that were output together with DTC P0A78-202.
      RESULT

      DTC No. Relevant Diagnosis
      P0A78-113, 128, 284, 286, 287, 505, 506, 806, 807, 808 Drive Motor "A" Inverter Performance
      NOTE:

      DTC P0A78-202 is stored after any of DTCs P0A78- 113, 128, 284, 286, 287, 505, 506, 806, 807 and 808 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.

    NEXT → See step   16 

  4. CHECK MOTOR CABLE See step   19 

    NG → See step   8 

    OK: Go to next step 

  5. REPLACE EV TRANSAXLE WITH MOTOR ASSEMBLY 

    Refer to COMPONENTS

    NEXT: Go to next step 

  6. REPLACE INVERTER WITH CONVERTER ASSEMBLY 

    Refer to COMPONENTS

    NEXT: Go to next step 

  7. CHECK DTC OUTPUT (EV) 
    1. Check the other DTCs that were output together with DTC P0A78-202.
      RESULT

      DTC No. Relevant Diagnosis
      P0A78-113, 128, 284, 286, 287, 505, 506, 806, 807, 808 Drive Motor "A" Inverter Performance
      NOTE:

      DTC P0A78-202 is stored after any of DTCs P0A78- 113, 128, 284, 286, 287, 505, 506, 806, 807 and 808 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.

    NEXT → See step   16 

  8. CHECK EV TRANSAXLE WITH MOTOR ASSEMBLY (MG2) 
    WARNING:

    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 information because this may cause a malfunction.

    2. Disconnect the motor cable from the EV transaxle with motor assembly.
    3. Using a milliohmmeter, measure the resistance according to the value(s) in the table below.
      Fig 1: Measuring Resistance Of EV Transaxle With Motor Assembly
      GTY385620Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT: 

      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
      U1-1 (W) - U1-3 (U) Power switch off 47.5 to 52.5 mΩ
      U1-2 (V) - U1-1 (W) Power switch off 47.8 to 52.8 mΩ
      U1-3 (U) - U1-2 (V) Power switch off 47.6 to 52.6 mΩ
      TEXT IN ILLUSTRATION

      *a Component without motor cable connected
      (EV Transaxle with Motor Assembly)

      HINT: 

      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)

    4. Using a megohmmeter set to 500 V, measure the insulation 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
      U1-1 (W) - Body ground Power switch off 100 MΩ or higher
      U1-2 (V) - Body ground Power switch off 100 MΩ or higher
      U1-3 (U) - Body ground Power switch off 100 MΩ or higher
    5. Connect the motor cable to the EV transaxle with motor assembly.

    NG → See step   12 

    OK: Go to next step 

  9. REPLACE MOTOR CABLE 

    Refer to COMPONENTS

    NEXT: Go to next step 

  10. REPLACE INVERTER WITH CONVERTER ASSEMBLY 

    Refer to COMPONENTS

    NEXT: Go to next step 

  11. CHECK DTC OUTPUT (EV) 
    1. Check the other DTCs that were output together with DTC P0A78-202.
      RESULT

      DTC No. Relevant Diagnosis
      P0A78-113, 128, 284, 286, 287, 505, 506, 806, 807, 808 Drive Motor "A" Inverter Performance
      NOTE:

      DTC P0A78-202 is stored after any of DTCs P0A78- 113, 128, 284, 286, 287, 505, 506, 806, 807 and 808 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.

    NEXT → See step   16 

  12. REPLACE MOTOR CABLE 

    Refer to COMPONENTS

    NEXT: Go to next step 

  13. REPLACE EV TRANSAXLE WITH MOTOR ASSEMBLY 

    Refer to COMPONENTS

    NEXT: Go to next step 

  14. REPLACE INVERTER WITH CONVERTER ASSEMBLY 

    Refer to COMPONENTS

    NEXT: Go to next step 

  15. CHECK DTC OUTPUT (EV) 
    1. Check the other DTCs that were output together with DTC P0A78-202.
      RESULT

      DTC No. Relevant Diagnosis
      P0A78-113, 128, 284, 286, 287, 505, 506, 806, 807, 808 Drive Motor "A" Inverter Performance
      NOTE:

      DTC P0A78-202 is stored after any of DTCs P0A78- 113, 128, 284, 286, 287, 505, 506, 806, 807 and 808 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.

    NEXT → See step   16 

  16. GO TO DTC CHART (HYBRID CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART 
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