Lexus IS250 · Service Manual COMMUNICATION SYSTEM

B1209

Diagnostic trouble codes

DESCRIPTION

  1. This DTC is detected when communication between the outer mirror control ECU (driver side outer mirror ECU) and gateway ECU stops for more than 10 seconds.
DTC No.
 DTC Detection Condition
 Trouble Area
B1209
 Outer mirror control ECU (driver side) Communication stops
  1. Outer mirror control ECU LH (driver side)
  2. Wire harness

WIRING DIAGRAM

B133423E02

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 B1209, repair the "+B or GND short malfunction of communication bus" DTCs first.


1. INSPECT FUSE (FR DOOR LH (LHD), FR DOOR RH (RHD), MPX-B)

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

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

  1. Remove the MPX-B fuse from the engine room J/B No. 1.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



 NG
REPLACE FUSE
OK


2. CHECK HARNESS AND CONNECTOR (OUTER MIRROR CONTROL ECU - BATTERY AND BODY GROUND)

  1. Disconnect the M10 ECU connector (for LHD).

  1. B110954E02
    Disconnect the L10 ECU connector (for RHD).

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

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    *1BDR (M10-6) - Body ground
    *2BDR (L10-6) - Body ground
    		 Always
    		 10 to 14 V

    Standard resistance:
    Tester Connection
    		 Specified Condition
    *1GND (M10-1) - Body ground
    *2GND (L10-1) - 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 M10 and J55 ECU connectors (for LHD).

  1. Disconnect the L10 and P33 ECU connectors (for RHD).B133215E02

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

    Standard resistance:
    Tester Connection
    		 Specified Condition
    *1MPX1 (M10-8) - MPX1 (J55-7)
    *1MPX1 (L10-8) - MPX1 (P33-27)
    		 Below 1 Ω
    *1MPX1 (M10-8) - Body ground
    *1MPX1 (L10-8) - Body ground
    		 Below 1 Ω

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



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE OUTER MIRROR CONTROL ECU (DRIVER SIDE)


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