Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: P/W Master Switch Communication Stop (B1206)

Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual / Power Source & Network / Networking / Lin Communication System / P/W Master Switch Communication Stop (B1206)

DESCRIPTION

This DTC is stored when LIN communication between the multiplex network master switch assembly and main body ECU (multiplex network body ECU) stops for 10 seconds or more.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1206

P/W Master Switch Communication Stop

No communication between multiplex network master switch assembly and main body ECU (multiplex network body ECU) for 10 seconds or more.
  • Multiplex network master switch assembly
  • Main body ECU (multiplex network body ECU)
  • Instrument panel junction block assembly
  • Wire harness or connector
  • ECU-B 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

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

2D-25 - 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 - MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY)

(a) Disconnect the N7 multiplex network master switch 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 (IG) to off and wait for 180 seconds or more without operating any switches.

Standard Resistance:

Tester Connection

Condition

Specified Condition

2D-25 - N7-17 (LIN1)

Engine switch off

Below 1 Ω

N7-17 (LIN1) or 2D-25 - Body ground

Engine switch off

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK HARNESS AND CONNECTOR (MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY - BATTERY, BODY GROUND)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

N7-11 (B) - N7-12 (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

N7-12 (GND) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

REPLACE MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY

(a) Replace the multiplex network master switch 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 B1206 is not output.

OK

END (MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY WAS DEFECTIVE)
NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

    Dtc Check / Clear
    DTC CHECK / CLEAR CHECK DTC (a) Connect the Techstream to the DLC3. (b) Turn the engine switch on (IG). (c) Turn the Techstream on. (d) Enter the following menus: Body Electrical / Main Body or Smart ...

    Driver Side Door ECU Communication Stop (B2321)
    DESCRIPTION This DTC is stored when LIN communication between the power window regulator motor assembly LH and main body ECU (multiplex network body ECU) stops for 10 seconds or more. DTC No. Det ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Safety Connect System: Indicator (Green) Circuit Short to Ground (B157111,B157113)
    DESCRIPTION This DTC is set when the DCM (telematics transceiver) detects an open or short in the manual (SOS) switch green indicator circuit of the manual (SOS) switch. The manual (SOS) switch green indicator illuminates after the engine switch is turned on (IG). If the safety connect system is not ...

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Can Communication System: Check Bus 1 Line for Short to +B
    DESCRIPTION There may be a short circuit between one of the CAN bus lines and +B when there is no resistance between terminal 23 (CA1H) of the network gateway ECU and terminal 16 (BAT) of the DLC3, or terminal 8 (CA1L) of the network gateway ECU and terminal 16 (BAT) of the DLC3. Symptom Troubl ...

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

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

    © 2026 Copyright www.lexusrx.net
    0.0084