Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: Lost Communication with Sliding Sunshade ECU (B2329)

Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual / Power Source & Network / Networking / Lin Communication System / Lost Communication with Sliding Sunshade ECU (B2329)

DESCRIPTION

This DTC is stored when LIN communication between the roof sunshade ECU (sliding roof drive gear assembly) and main body ECU (multiplex network body ECU) stops for 10 seconds or more.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B2329

Lost Communication with Sliding Sunshade ECU

No communication between roof sunshade ECU (sliding roof drive gear assembly) and main body ECU (multiplex network body ECU) for 10 seconds or more.
  • Roof sunshade ECU (sliding roof drive gear assembly)
  • Main body ECU (multiplex network body ECU)
  • Instrument panel junction block assembly
  • Wire harness or connector
  • S/ROOF NO. 2 fuse

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

    Click here

  • When the roof sunshade ECU (sliding roof drive gear sub-assembly) is replaced or removed and reinstalled, it is necessary to perform initialization.

    Click here

PROCEDURE

1.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Remove the instrument panel junction block assembly.

Click here

*a

Component without harness connected

(Instrument Panel Junction Block Assembly)

-

-

(b) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

(c) Measure the resistance according to the value(s) in the table below.

HINT:

This inspection is to check the LIN communication line in the instrument panel junction block assembly that connects the wire harness to the built-in main body ECU (multiplex network body ECU).

Standard Resistance:

Tester Connection

Condition

Specified Condition

2B-17 - MB-16 (LIN2)

Always

Below 1 Ω
NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

OK

2.

CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - ROOF SUNSHADE ECU (SLIDING ROOF DRIVE GEAR ASSEMBLY))

(a) Disconnect the w1 roof sunshade ECU (sliding roof drive gear assembly) connector.

(b) Measure the resistance according to the value(s) in the table below.

NOTICE:

Make sure that each ECU is in sleep mode before performing the inspection. To enter sleep mode, turn the engine switch from ON to off and wait for 180 seconds or more without operating any switches.

Standard Resistance:

Tester Connection

Condition

Specified Condition

2B-17 -w1-7 (LIN)

Engine switch off

Below 1 Ω

w1-7 (LIN) or 2B-17 - Body ground

Engine switch off

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK HARNESS AND CONNECTOR (ROOF SUNSHADE ECU (SLIDING ROOF DRIVE GEAR ASSEMBLY) - BATTERY, BODY GROUND)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

w1-1 (+B) - w1-2 (E)

Always

11 to 14 V

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

w1-2 (E) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

REPLACE ROOF SUNSHADE ECU (SLIDING ROOF DRIVE GEAR ASSEMBLY)

(a) Replace the roof sunshade ECU (sliding roof drive gear assembly).

Click here

NEXT

5.

CHECK FOR DTC

(a) Clear the DTCs.

Click here

Body Electrical > Main Body > Clear DTCs

(b) Recheck for DTCs.

Body Electrical > Main Body > Trouble Codes

OK:

DTC B2329 is not output.

OK

END (ROOF SUNSHADE ECU (SLIDING ROOF DRIVE GEAR ASSEMBLY) WAS DEFECTIVE)
NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

    LIN Communication Bus Malfunction (B2325)
    DESCRIPTION If the main body ECU (multiplex network body ECU) detects a communication error with an ECU connected to the door bus lines for 7 seconds or more, DTC B2325 will be stored. DTC No. De ...

    Communication Malfunction between ECUs Connected by LIN (B2785)
    DESCRIPTION If the certification ECU (smart key ECU assembly) detects a communication error with an ECU connected to the certification bus lines for 7 sedonds or more, DTC B2785 will be stored. DTC ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Differential System: Precaution
    PRECAUTION Before disassembly, clean the outside of the differential assembly and remove any sand or mud to prevent it from entering the inside of the assembly during disassembly and installation. When removing an installed part made of light alloy such as the differential side bearing retainer ...

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Lin Communication System: Lost Communication with Power Source Control (B278C)
    DESCRIPTION This DTC is stored when LIN communication between the certification ECU (smart key ECU assembly) and power management control ECU stops for 10 seconds or more. DTC No. Detection Item DTC Detection Condition Trouble Area B278C Lost Communication with Power Source Control ...

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

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

    © 2026 Copyright www.lexusrx.net
    0.01