Power Source Mode does not Change to ON (ACC) [12/2019 - 11/2023]: 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 

   Body Electrical > Starting Control > 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 [12/2019 - 10/2021]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2021 - 10/2022]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2022 - 11/2023] 

Result: 

A 

See step  2

1. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Certification ECU (Smart Key ECU Assembly))

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   H48-16 (ACCD) - Body ground	Ignition switch ACC → Ignition switch ON	1 V or less → 9 V or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

OK 

See step  3

1. Disconnect the H48 certification ECU (smart key ECU assembly) connector.
2. Disconnect the 4A, 4B and 4F instrument panel junction block assembly connectors.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H48-16 (ACCD) - 4A-30	Always	Below 1 Ω
   4B-3 - Body ground	Always	Below 1 Ω
   H48-16 (ACCD) or 4A-30 - Other terminals and body ground	Always	10 kΩ or higher

4. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   4F-1 - Body ground	Always	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Remove the instrument panel junction block assembly.

   Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

2. Connect all of the instrument panel junction block assembly connectors.
3. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component with harness connected (Instrument Panel Junction Block Assembly)

   -

   -

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   4A-40 - Body ground	Ignition switch ON	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]