DTC B1279: Lost Communication with Humidity/Rain Sensor LIN [09/2015 - ]: Procedure

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [09/2015 - ]

   Body Electrical > Main Body > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

1. Turn the engine switch on (IG).
2. Check for DTCs.

   Refer to DTC CHECK / CLEAR [09/2015 - ]

   Body Electrical > Main Body > Trouble Codes 

   Result

   Result	Proceed to
   DTC B1278 is not output.	A
   DTC B1278 is output.	B

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2015 - 08/2016]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2016 - 12/2017]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 08/2019]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

Result: 

B 

See step  3

1. Disconnect the J9 main body ECU (multiplex network body ECU) connector.
2. Disconnect the U3 rain sensor connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   J9-8 (LIN3) - U3-3 (MPX)	Always	Below 1 Ω
   J9-8 (LIN3) or U3-3 (MPX) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   U3-4 (SIG) - U3-2 (ES)	Engine switch off	Below 1 V
   	Engine switch on (IG)	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  6

Result: 

OK 

See step  5

1. Replace the rain sensor with a new or known good one.

   Refer to REMOVAL [09/2015 - ]

2. Turn the engine switch on (IG).
3. Check for DTCs.

   Refer to DTC CHECK / CLEAR [09/2015 - ]

   Body Electrical > Main Body > Trouble Codes 

   Result

   Result	Proceed to
   DTC B1279 is not output.	A
   DTC B1279 is output.	B

Result: 

A 

END 

Result: 

B 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2015 - 08/2016]  , or refer to  REMOVAL [08/2016 - 08/2019]  , or refer to  REMOVAL [08/2019 - ] 

1. Remove the map light assembly.

   Refer to REMOVAL [09/2015 - ]

2. Inspect the map light assembly.

   Refer to INSPECTION [09/2015 - ]

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

NG 

REPLACE MAP LIGHT ASSEMBLY. Refer to  REMOVAL [09/2015 - ]