Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: Software Incompatibility with Body Control Module "B" (U1331)

Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual / Audio & Visual & Telematics / Park Assist / Monitoring / Blind Spot Monitor System / Software Incompatibility with Body Control Module "B" (U1331)

DESCRIPTION

This DTC is stored when the destination information of the main body ECU (multiplex network body ECU) does not match that of the blind spot monitor sensors.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

U1331

Software Incompatibility with Body Control Module "B"

Destination information of the main body ECU and blind spot monitor sensor do not match
  • Main body ECU (multiplex network body ECU)
  • Blind spot monitor sensor LH
  • Blind spot monitor sensor RH

CAUTION / NOTICE / HINT

NOTICE:

  • When checking for DTCs, make sure that the blind spot monitor system is turned on.
  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

    Click here

PROCEDURE

1.

CONFIRM PART NUMBER (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(a) 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 to the vehicle is correct.

OK:

The part number is correct.

NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

OK

2.

CHECK DTC

(a) Turn the engine switch off.

(b) Turn the engine switch on (IG).

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

Body Electrical > Blind Spot Monitor Master > Trouble Codes Body Electrical > Blind Spot Monitor Slave > Trouble Codes

Result

Proceed to

No DTCs are output.

A

DTC U1331 is output ("Blind Spot Monitor Master").

B

DTC U1331 is output ("Blind Spot Monitor Slave").

C
A

USE SIMULATION METHOD TO CHECK

B

REPLACE BLIND SPOT MONITOR SENSOR LH

C

REPLACE BLIND SPOT MONITOR SENSOR RH

    Lost Communication with Blind Spot Monitor Slave Module (U0232)
    DESCRIPTION This DTC is stored when the blind spot monitor sensor LH judges that there is a communication problem with the blind spot monitor sensor RH. DTC No. Detection Item DTC Detection Con ...

    Power Source Circuit
    DESCRIPTION This circuit provides power to operate the blind spot monitor sensor. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: Inspect the fuses for circuits related to this system before performin ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Power Window Control System: Diagnosis System
    DIAGNOSIS SYSTEM DESCRIPTION (a) Power window control system data and Diagnostic Trouble Codes (DTCs) can be read through the vehicle Data Link Connector 3 (DLC3). When the system seems to be malfunctioning, use the Techstream to check for malfunctions and perform repairs. CHECK DLC3 (a) Check the D ...

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Automatic Transaxle System: Monitor Drive Pattern
    MONITOR DRIVE PATTERN MONITOR DRIVE PATTERN FOR ECT CAUTION: Perform the following procedure on a level surface while strictly observing all traffic laws and speed limits. HINT: Performing this drive pattern is one method to simulate ECM (ECT) malfunction detection conditions. Some DTCs may not be d ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    © 2026 Copyright www.lexusrx.net
    0.0094