Power Source Mode does not Change to ON (ACC) [10/2022 - ]: Procedure
WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK FOR DTC
- 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 [10/2022 - ]
Result:
A
See step 2
- Using the GTS, check for certification ECU (smart key ECU assembly) DTCs.
- CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTION BOX ASSEMBLY - POWER SOURCE)
- Disconnect the A69 power distribution box assembly connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition A69-1 - 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
- CHECK POWER DISTRIBUTION BOX ASSEMBLY (ACC RELAY)
- Remove the power distribution box assembly.
Refer to REMOVAL [10/2022 - 08/2023] , or refer to REMOVAL [08/2023 - ]
- Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.
- Connect the auxiliary battery terminal (+) to the C89-38 terminal.
- Connect the auxiliary battery terminal (-) to the C89-36 terminal.
*a Component without harness connected
(Power Distribution Box Assembly)- - - Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A69-1 - C89-12 Auxiliary battery voltage applied between terminals C89-38 and C89-36 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 [10/2022 - 08/2023] , or refer to REMOVAL [08/2023 - ]
- Remove the power distribution box assembly.