Lexus IS250 · Service Manual COMMUNICATION SYSTEM

B1206

Diagnostic trouble codes

DESCRIPTION

  1. This DTC is detected when communication between the multiplex network master switch (power window master switch) and 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 (power window master switch)
  2. Wire harness

WIRING DIAGRAM

B131085E01

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. INSPECT FUSE (FR DOOR LH)

  1. Remove the FR DOOR LH fuse from the main body ECU LH (cowl side J/B LH).

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



 NG
REPLACE FUSE
OK


2. CHECK WIRE HARNESS (POWER WINDOW MASTER SWITCH - BATTERY AND BODY GROUND)

  1. B110948E02
    Disconnect the M7 switch connector (for LHD).

  1. Disconnect the L17 switch connector (for RHD).

  1. Turn the engine switch on (IG).

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

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    *1BDR (M7-10) - Body ground
    *2BDR (L17-10) - Body ground
    		 Always
    		 10 to 14 V

    HINT:
    1. *1: LHD
    2. *2: RHD

    Standard resistance:
    Tester Connection
    		 Specified Connection
    *1GND (M7-2) - Body ground
    *2GND (L17-2) - Body ground
    		 Below 1 Ω

    HINT:
    1. *1: LHD
    2. *2: RHD



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3. CHECK RESISTANCE OF COMMUNICATION LINE

  1. Disconnect the M7, Q3 and P33 ECU connectors (for LHD).

  1. Disconnect the L17, RJ and P33 ECU connector (for RHD).B133214E01

  1. Measure the resistance between the specified terminals on the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    *1MPX1 (M7-7) - MPX1 (Q3-15)
    *2MPX1 (L17-7) - MPX1 (P33-27)
    		 Below 1 Ω
    *1MPX2 (M7-8) - MPX2 (P33-28)
    *2MPX2 (L17-8) - MPX2 (RJ-21)
    		 Below 1 Ω

    HINT:
    1. *1: LHD
    2. *2: RHD

    Result:
    Result
    		 Proceed to
    Both are OK
    		 A
    One is OK
    		 B
    Both are NG
    		 C



B
REPAIR OR REPLACE HARNESS OR CONNECTOR AND REPLACE POWER WINDOW MASTER SWITCH

C
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPLACE POWER WINDOW MASTER SWITCH


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