RX400h · Service Manual COMMUNICATION SYSTEM

B1206 Multiplex network master switch communication stops

Diagnostic trouble codes

DESCRIPTION

  1. This DTC is detected when communication between the multiplex network master switch assembly (P/W Master Switch) and multiplex network gateway ECU stops for more than 10 seconds.
DTC No.
 DTC Detection Condition
 Trouble Area
B1206
 Multiplex network master switch communication stops
  1. Multiplex network master switch assembly
  2. Wire harness

WIRING DIAGRAM

B110988E05

INSPECTION PROCEDURE

HINT:
When "+B of GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1206, repair the "+B or GND short malfunction of communication bus" DTCs first.


1. CHECK OPERATION

  1. Turn the ignition switch on.

  1. Check that the driver side power window can be operated using the multiplex network master switch.

    HINT:
    With this inspection, the multiplex network master switch CPU can be diagnosed if it works normally or not.

    OK:
    Power window can be operated using multiplex network master switch.



 OK
Go to step 4
NG


2. INSPECT FUSE (ECU-B No.1)

  1. Remove the ECU-B No.1 fuse from the fusible link block.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



 NG
REPLACE FUSE
OK


3. CHECK WIRE HARNESS (MULTIPLEX NETWORK MASTER SWITCH - BATTERY AND BODY GROUND)

  1. B109185E12
    Disconnect the P19 switch connector.

  1. Measure the voltage of the wire harness side connector.

    Standard voltage:
    Tester Connection
    		 Specified Connection
    P19-9 (CPUB) - Body ground
    		 10 to 14 V

  1. Measure the resistance of the wire harness side connector.

    Standard resistance:
    Tester Connection
    		 Specified Connection
    P19-2 (GND) - Body ground
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4. CHECK RESISTANCE OF COMMUNICATION LINE

  1. Disconnect the G1 ECU connector (w/o Driving position memory).

  1. Disconnect the T4 ECU connector (w/ Driving position memory).

  1. Disconnect the 1E instrument panel connector.B111048E02

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    P19-8 (MPX2) - 1E-7 (MPX1)
    		 Below 1 Ω
    P19-7 (MPX1) - T4-5 (MPX1) (*1)
    		 Below 1 Ω
    P19-7 (MPX1) - G1-12 (MPD2) (*2)
    		 Below 1 Ω

    *1: w/ Driving Position Memory*2: w/o Driving Position Memory



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE MULTIPLEX NETWORK MASTER SWITCH


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