DTC B1279: Lost Communication with Humidity/Rain Sensor LIN [12/2017 - 10/2023]: Procedure

1. Clear the DTC.

   Refer to DTC CHECK / CLEAR [12/2017 - 10/2023]

   Body Electrical > Main Body > Clear DTCs 

2. Turn the engine switch on (IG) and wait for at least 10 seconds.
3. Check for DTCs.

   Refer to DTC CHECK / CLEAR [12/2017 - 10/2023]

   Body Electrical > Main Body > Trouble Codes 

   Result

   Result	Proceed to
   DTC B1279 is not output.	A
   DTC B1279 is output.	B
   DTC B1279 and DTC B1373 are output.	C

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 09/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2018 - 10/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2020 - 11/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 10/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - 10/2023] 

Result: 

C 

GO TO DTC B1373. Refer to  DTC B1373: Lost Communication with Wiper System LIN BUS [12/2017 - 10/2023]  

Result: 

B 

See step  2

1. Disconnect the G13 main body ECU (multiplex network body ECU) connector.
2. Disconnect the N29 rain sensor connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G13-3 (LIN3) - N29-3 (MPX)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Disconnect the N29 rain sensor connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   N29-2 (ES) - Body ground	Always	Below 1 Ω

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   N29-4 (SIG) - Body ground	Engine switch off	Below 1 V
   	Engine switch on (IG)	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE RAIN SENSOR. Refer to  REMOVAL [12/2017 - ] 

Result: 

NG 

See step  4

1. Remove the map light assembly.

   Refer to REMOVAL [12/2017 - ]

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A-1 (IG) - A-2 (IG2)	Always	Below 1 Ω
   B-22 (GND) - A-25 (GND2)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

NG 

REPLACE MAP LIGHT ASSEMBLY. Refer to  REMOVAL [12/2017 - ]