DTC B1280: Left Side Junction Block ECU Communication Stop: Procedure

1. Disconnect the LD junction block connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   LD-18 (MPXB) - Body ground	Always	11 to 14 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   LD-3 (GND) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Cowl Side Junction Block LH)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the Q3, A30, 2F and Q36 connectors.

   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
   Q3-15 (MPX1) - Q36-24 (MPX1)	Always	Below 1 Ω
   A30-17 (MPX2) - 2F-6 (MPX2)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Main Body ECU LH (Cowl Side Junction Block LH))	*2	Front view of wire harness connector (to Main Body ECU LH (Cowl Side Junction Block LH))
   *3	Front view of wire harness connector (to Metaltop Control ECU (Sliding Roof Control ECU Assembly))	*4	Front view of wire harness connector (to Front Controller (Engine Room Relay Block No. 2))

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Replace the main body ECU LH (cowl side junction block LH).

NEXT: Go to next step 

1. Clear the DTC. Refer to DTC CHECK / CLEAR [08/2012 - ] .
2. Recheck for DTCs.

   OK

   DTC B1280 is not output.

NG → See step   5 

OK → END (MAIN BODY ECU LH (COWL SIDE JUNCTION BLOCK LH) WAS DEFECTIVE)