Power Source Mode does not Change to ON (IG) [10/2023 - ]: Procedure

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

   Body Electrical > Power Source Control > Trouble Codes 

   Body Electrical > Smart Access > Trouble Codes 

   Result

   Result	Proceed to
   DTCs are not output	A
   Smart access system with push-button start (for Start Function) DTCs are output	B

Result: 

B 

GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2023 - ] 

Result: 

A 

See step  2

1. Disconnect the A124 certification ECU (smart key ECU assembly) connector.
2. Disconnect the 8B and 8C power distribution box assembly connectors.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   8C-17 - A124-24 (IGPD)	Always	Below 1 Ω
   8B-10 - A124-11 (IGRD)	Always	Below 1 Ω
   8B-36 - Body ground	Always	Below 1 Ω
   8C-17 or A124-24 (IGPD) - Other terminals and body ground	Always	10 kΩ or higher
   8B-10 or A124-11 (IGRD) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Connect the A124 certification ECU (smart key ECU assembly) connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A124-11 (IGRD) - Body ground	Ignition switch ACC → Ignition switch ON	1 V or less → 9 V or higher
   A124-24 (IGPD) - 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 [10/2023 - ] 

Result: 

OK 

See step  4

1. Disconnect the A124 certification ECU (smart key ECU assembly) connector.
2. Disconnect the 8B, 8C, 8E and 8K power distribution box assembly connectors.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   8K-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  5

1. Remove the power distribution box assembly.

   Refer to REMOVAL [10/2023 - ]

2. Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component without harness connected (Power Distribution Box Assembly)

   -

   -

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   8C-17 - 8E-14	Always	Below 1 Ω

4. Connect the auxiliary battery terminal (+) to the 8B-10 terminal.
5. Connect the auxiliary battery terminal (-) to the 8B-36 terminal.
6. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   8K-1 - 8C-36	Auxiliary battery voltage applied between terminals 8B-10 and 8B-36	Below 1 Ω
   8K-1 - 8B-39	Auxiliary battery voltage applied between terminals 8B-10 and 8B-36	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [10/2023 - ] 

Result: 

OK 

See step  6

1. Remove the IGP NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   8E-14 - IGP NO. 1 relay terminal 1	Always	Below 1 Ω
   IGP NO. 1 relay terminal 2 - Body ground	Always	Below 1 Ω
   8E-14 or IGP NO. 1 relay terminal 1 - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  7

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 - 5	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω
   	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	IGP NO. 1 Relay

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

NG 

REPLACE IGP RELAY