DTC B2405: Sub Bus LIN Module Communication Malfunction: Procedure

1. Disconnect the S62 junction block connector.
   Fig 1: Identifying S62 Rear Junction Block ECU & X6 Map Light Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the X6 light connector.
3. Measure the resistance and voltage according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   S62-9 (LIN) - X6-2 (LIN)	Always	Below 1 Ω
   S62-9 (LIN) or X6-2 (LIN) - Body ground	Always	10 kΩ or higher

   Standard voltage

   Tester Connection	Condition	Specified Condition
   S62-9 (LIN) or X6-2 (LIN) - Body ground	Always	Below 1 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the X4 light connector.
   Fig 2: Identifying X4 Map Light Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance and voltage according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   X4-16 (GND9) - Body ground	Always	Below 1 Ω

   Standard voltage

   Tester Connection	Condition	Specified Condition
   X4-6 (+B) - Body ground	Always	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Temporarily replace the map light with a new or normally functioning one. Refer to REMOVAL .
2. Clear the DTC. Refer to DTC CHECK / CLEAR .

NEXT: Go to next step 

1. Recheck for DTC. Refer to DTC CHECK / CLEAR .

   OK

   DTC B2405 is not output.

NG → REPLACE LUGGAGE ROOM JUNCTION BLOCK (REAR JUNCTION BLOCK ECU) 

OK → END (MAP LIGHT IS DEFECTIVE)