DTC U1331: Software Incompatibility with Body Control Module "B" [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

CONFIRM PART NUMBER (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))
1. Check the main body ECU (multiplex network body ECU) part number.
  1. Check if the part number of the main body ECU (multiplex network body ECU) installed on the vehicle is correct.
    OK
    
    The part number is correct.
NG → See step 3

OK: Go to next step

CHECK DTC

Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .

Recheck for DTCs and check if the same DTC is output again.

Result

Result	Proceed to
No DTC is output	A
DTC is output from the blind spot monitor sensor LH (Master)	B
DTC is output from the blind spot monitor sensor RH (Slave)	C

B → See step 6

C → See step 5

A → See step 4

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to REMOVAL [08/2013 - ]
USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2013 - ]
REPLACE BLIND SPOT MONITOR SENSOR RH. Refer to REMOVAL [08/2013 - ]
REPLACE BLIND SPOT MONITOR SENSOR LH. Refer to REMOVAL [08/2013 - ]