DTC B1279: Lost Communication with Humidity/Rain Sensor LIN [10/2019 - 10/2020]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Trouble Codes.
5. Check for DTCs.

   Body Electrical > Main Body > Trouble Codes 

   Result

   Result	Proceed to
   Only DTC B1279 is output	A
   DTC B1279 and B1373 are output	B

Result: 

B 

GO TO DTC B1373. Refer to  DTC B1373: Lost Communication with Wiper System LIN BUS [10/2019 - 10/2020]  

Result: 

A 

See step  2

1. Disconnect the F41 main body ECU (multiplex network body ECU) connector.
2. Disconnect the S2 rain sensor connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   F41-3 (LIN3) - S2-3 (MPX)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Check for voltage and pulses according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   F41-3 (LIN3) - Body ground	Ignition switch off	Below 1 V
   	Ignition switch ON	Pulse generation

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [10/2018 - 07/2022] 

Result: 

OK 

See step  4

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   S2-4 (SIG) - Body ground	Ignition switch off	Below 1 V
   	Ignition switch ON	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  7

Result: 

OK 

See step  5

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   S2-2 (ES) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE RAIN SENSOR. Refer to  REMOVAL [10/2018 - ] 

Result: 

NG 

See step  6

1. Remove the map light assembly.

   Refer to REMOVAL [10/2018 - ]

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   S7-19 (GND) - S7-21 (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 [10/2018 - ] 

1. Remove the map light assembly.

   Refer to REMOVAL [10/2018 - ]

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   S7-1 (IG) - S7-14 (IG2)	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 [10/2018 - ]