DTC P0A09-591: DC / DC Converter Status Circuit Low Input [12/2014 - ]: Procedure

NG → CONNECT SECURELY 

OK: Go to next step 

NG → CONNECT SECURELY 

OK: Go to next step 

1. Connect an oscilloscope between the hybrid vehicle control ECU terminals specified in the table below.
2. Turn the ignition switch to ON (IG).
3. Measure the waveform.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Item	Content
   Terminal	A38-16 (VLO) - G57-6 (E1)
   Equipment Setting	5 V/DIV., 50 ms/DIV.
   Condition	Ignition switch ON (IG)

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Hybrid Vehicle Control ECU)

   OK

   The waveform appears as shown in the illustration.

   HINT: 

   • Perform this inspection with the hybrid vehicle control ECU connector connected.
   • The waveform varies depending on the specified DC/DC converter voltage.
4. Turn the ignition switch off.

NG → See step   6 

OK: Go to next step 

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

NEXT: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON (READY).
3. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.
4. Check if DTCs are output.

   Result

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

5. Turn the ignition switch off.

B → See step   8 

A → See step   10 

1. Check that the service plug grip is not installed.
   NOTE:

   After removing the service plug grip, do not turn the ignition switch to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

2. Disconnect connector A47 from the inverter with converter assembly.
3. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   A47-3 (VLO) - Body ground	Ignition switch off	370 to 430 kΩ

   TEXT IN ILLUSTRATION
   
   

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

4. Connect the inverter with converter assembly connector.

NG → See step   7 

OK → See step   9 

1. Check that the service plug grip is not installed.
   NOTE:

   After removing the service plug grip, do not turn the ignition switch to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

2. Disconnect connector A47 from the inverter with converter assembly.
3. Disconnect connector A38 from the hybrid vehicle control ECU.
4. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   A47-3 (VLO) - A38-16 (VLO)	Ignition switch off	Below 1 Ω
   A47-3 (VLO) or A38-16 (VLO) - Body ground and other terminals	Ignition 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 Hybrid Vehicle Control ECU)

5. Connect the inverter with converter assembly connector.
6. Connect the hybrid vehicle control ECU connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   8