DTC B1279: Lost Communication with Humidity/Rain Sensor LIN [10/2020 - ]: Procedure
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus UX 250h, 2023 Lexus UX 250h, 2022 Lexus UX 250h, 2021 Lexus UX 250h, and 2020 Lexus UX 250h. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK HARNESS AND CONNECTOR (RAIN SENSOR - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))
- Disconnect the S2 rain sensor connector.
- Disconnect the F41 main body ECU (multiplex network body ECU) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition S2-3 (MPX) - F41-3 (LIN3) Always Below 1 Ω S2-3 (MPX) or F41-3 (LIN3) - Body ground Always 10 kΩ or higher Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 2
- INSPECT MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)
*a Component without harness connected
(Main Body ECU (Multiplex Network Body ECU))- Using an oscilloscope, check the waveform.
OK
Tester Connection Switch Condition Specified Condition F41-3 (LIN3) -Body ground Power switch on (IG) Pulse generation Result
Proceed to OK NG
Result:
OK
REPLACE RAIN SENSOR. Refer to REMOVAL [10/2018 - ]
Result:
NG
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to REMOVAL [10/2018 - 07/2022] , or refer to REMOVAL [07/2022 - ]
- Using an oscilloscope, check the waveform.