Bus Buffer ECU Communication Stop Mode [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 VEHICLE TYPE
- Check whether dealer installed options that support CAN communication are installed.
Result
Result Proceed to Installed A Not installed B
Result:
B
See step 3
Result:
A
See step 2
- Check whether dealer installed options that support CAN communication are installed.
- CHECK FOR OPEN IN CAN BUS LINES (OPTION CONNECTOR (BUS BUFFER ECU) MAIN LINE)
- Disconnect the cable from the negative (-) battery terminal.
- Disconnect the C77 option connector (bus buffer ECU) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition C77-2 (CAN+) - C77-1 (CAN-) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPAIR OR REPLACE CAN COMPATIBLE OPTIONAL DEVICE
Result:
NG
REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (OPTION CONNECTOR (BUS BUFFER ECU))
- CHECK FOR DTC
- Initialize the ECU.
Body Electrical > Central Gateway > Utility
Tester Display Initialization Body Electrical > Main Body > Utility
Tester Display Initialization - Clear the DTCs.
Body Electrical > Main Body > Clear DTCs
- Read the DTCs.
Body Electrical > Main Body > Trouble Codes
Result
Result Proceed to DTC U1117-87 is not output from main body ECU (multiplex network body ECU) A DTC U1117-87 is output from main body ECU (multiplex network body ECU) B
Result:
A
END
Result:
B
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to REMOVAL [10/2022 - 08/2023] , or refer to REMOVAL [08/2023 - ]
- Initialize the ECU.