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

NG → See step   4 

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Refer to COMPONENTS

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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 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.

5. Turn the power switch off.

NEXT → See step   16 

NG → See step   8 

OK: Go to next step 

Refer to COMPONENTS

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Refer to COMPONENTS

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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 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.

5. Turn the power switch off.

NEXT → See step   16 

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. Remove the inverter with converter assembly.
3. Disconnect the motor cable from the hybrid vehicle transaxle assembly.
4. Check MG2 for an interphase short using a milliohmmeter.
   Fig 1: Checking MG2 For An Interphase Short

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Using a milliohmmeter, measure the resistance according to the value(s) in the table below.

      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
      e2-1 (W) - e2-3 (U)	Power switch off	149 to 165 mΩ
      e2-2 (V) - e2-1 (W)	Power switch off	148 to 164 mΩ
      e2-3 (U) - e2-2 (V)	Power switch off	154 to 170 mΩ

      TEXT IN ILLUSTRATION
      
      

      *a	Component without motor cable connected (Hybrid Vehicle Transaxle 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)
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
   e2-1 (W) - Body ground	Power switch off	100 MΩ or higher
   e2-2 (V) - Body ground	Power switch off	100 MΩ or higher
   e2-3 (U) - Body ground	Power switch off	100 MΩ or higher

6. Connect the motor cable.
7. Install the inverter with converter assembly.

NG → See step   12 

OK: Go to next step 

Refer to COMPONENTS

NEXT: Go to next step 

Refer to COMPONENTS

NEXT: Go to next step 

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 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.

5. Turn the power switch off.

NEXT → See step   16 

Refer to COMPONENTS

NEXT: Go to next step 

Refer to COMPONENTS

NEXT: Go to next step 

Refer to COMPONENTS

NEXT: Go to next step 

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 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.

5. Turn the power switch off.

NEXT → See step   16