DTC P31C0-123: EV Battery No. 1 Self-diagnosis Permit Signal Circuit; DTC P31C5-123: EV Battery No. 2 Self-diagnosis Permit Signal Circuit: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / EV Battery / Trouble Codes.
5. Read output DTCs.
   RESULT
   
   

   Result	Proceed to
   P31C0-123 or P31C5-123 is output	A
   P31C0-123 or P31C5-123 and other DTCs are also output	B

6. Turn the power switch off.

B → See step   7 

A: Go to next step 

1. Connect an oscilloscope between the power management control ECU terminals specified in the table below.
   Fig 1: Identifying Power Management Control ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

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

2. Turn the power switch on (IG).
3. Measure the waveform.
   Fig 2: Identifying Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Item	Content
   Terminal	C22-14 (SDG) - C21-24 (E1) C22-15 (SDG2) - C21-24 (E1)
   Equipment Setting	2 V/DIV, 200 ms/DIV
   Condition	Power switch on (IG)

   OK

   The waveform appears as shown in the illustration.

4. Turn the power switch off.

NG → See step   6 

OK: Go to next step 

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.

   Fig 3: Measuring Resistance Of Power Management Control ECU - Electric Vehicle Battery Assembly Harness & Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the power management control ECU connector.
3. Disconnect the electric vehicle battery assembly connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   C22-14 (SDG) - Gi1-16	Power switch off	Below 1 Ω
   C22-15 (SDG2) - Gi1-17	Power switch off	Below 1 Ω
   C22-14 (SDG) or Gi1-16 - Body ground and other terminals	Power switch off	10 kΩ or higher
   C22-15 (SDG2) or Gi1-17 - Body ground and other terminals	Power switch off	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *a	Rear view of wire harness connector (to Power Management Control ECU)
   *b	Front view of wire harness connector (to Electric Vehicle Battery Assembly)

5. Connect the electric vehicle battery assembly connector.
6. Connect the power management control ECU connector.

NG → See step   5 

OK: Go to next step 

Refer to COMPONENTS

NEXT → See step   8 

NEXT → See step   8 

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   8