DTC P0A09-591: DC / DC Converter Status Circuit Low Input: Procedure

NG → CONNECT SECURELY 

OK: Go to next step 

NG → CONNECT SECURELY 

OK: Go to next step 

1. Connect an oscilloscope between the power management control ECU terminals specified in the table below.
2. Turn the power switch on (IG).
3. Measure the waveform.
   Fig 1: Identifying Power Management Control ECU Connector Terminals With Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Item	Content
   Terminal	A23-20 (VLO) - C21-24 (E1)
   Equipment Setting	5 V/DIV., 50 ms/DIV.
   Switch Condition	Power switch on (IG)

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Power Management Control ECU)

   OK

   The waveform appears as shown in the illustration.

   HINT: 

   • Perform this inspection with the power management control ECU connector connected.
   • The cycle will vary depending on the specified voltage of the DC/DC converter.
4. Turn the power switch off.

NG → See step   7 

OK: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Enter the following menus: Powertrain / EV / Trouble Codes.
4. Read and record the DTCs and freeze frame data.
5. Clear DTCs and freeze frame data.
6. Turn the power switch off.

NEXT: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (READY).
3. Enter the following menus: Powertrain / EV / Trouble Codes.
4. Check if DTCs related to the EV control system are output.

   Result

   Result	Proceed to
   DTC P0A09-591 is not output.	A
   DTC P0A09-591 is output again.	B

5. Turn the power switch off.

B → See step   9 

A: Go to next step 

Refer to CHECK FOR INTERMITTENT PROBLEMS

OK → See step   9 

NG → REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA 

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 inverter with converter assembly connector.
3. Measure the resistance according to the value(s) in the table below.
   Fig 2: Measuring Resistance Of Inverter With Converter Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   A21-3 (VLO) - Body ground	Power switch off	370 to 430 kΩ

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Inverter with Converter Assembly)

4. Reconnect the inverter with converter assembly connector.

NG → See step   8 

OK → See step   10 

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 inverter with converter assembly connector.
3. Disconnect the power management control ECU connector.
4. Measure the resistance according to the value(s) in the table below.
   Fig 3: Measuring Resistance Of Inverter With Converter Assembly - Power Management Control ECU Harness & Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   A21-3 (VLO) - A23-20 (VLO)	Power switch off	Below 1 Ω
   A21-3 (VLO) or A23-20 (VLO) - Body ground and other terminals	Power switch off	10 kΩ or higher

   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)

5. Reconnect the inverter with converter assembly connector.
6. Reconnect the power management control ECU connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Even though it has been determined that the power management control ECU needs to be replaced, make sure to inspect the voltage difference between No. 1 EV battery and No. 2 EV battery before replacing it.

NEXT → See step   11