Power Source Mode does not Change to ON (ACC) [07/2020 - ]: Procedure

1. Using the GTS, check for certification ECU (smart key ECU assembly) DTCs.

   Body Electrical > Power Source Control > Trouble Codes 

   Body Electrical > Smart Key > Trouble Codes 

   Result

   Result	Proceed to
   DTCs are not output	A
   Smart key system (for Start Function) DTCs are output	B

Result: 

B 

GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [07/2020 - 12/2021]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2021 - ] 

Result: 

A 

See step  2

1. Disconnect the 4F power distribution box assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   4F-1 - Body ground	Ignition switch off	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Remove the power distribution box assembly.

   Refer to REMOVAL [07/2020 - 10/2022] , or refer to REMOVAL [10/2022 - ]

2. Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.
3. Connect the auxiliary battery terminal (+) to the 4B-39 terminal.
4. Connect the auxiliary battery terminal (-) to the 4B-36 terminal.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component without harness connected (Power Distribution Box Assembly)

   -

   -

5. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4F-1 - 4B-12	Battery voltage applied between terminals 4B-39 and 4B-36	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

NG 

REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [07/2020 - 10/2022]  , or refer to  REMOVAL [10/2022 - ]