Lexus IS250 · Service Manual COMMUNICATION SYSTEM

B1249

Diagnostic trouble codes

DESCRIPTION

  1. This DTC is detected when communication between the double door lock ECU and gateway ECU stops for more than 10 seconds.
DTC No.
 DTC Detection Condition
 Trouble Area
B1262
 Double door lock ECU communication stops
  1. Double door lock ECU
  2. Wire harness

WIRING DIAGRAM

B133425E01

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 B1249, repair the "+B or GND short malfunction of communication bus" DTCs first.


1. INSPECT FUSE (MPX-B, DOOR DL)

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

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

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



 NG
REPLACE FUSE
OK


2. CHECK WIRE HARNESS (DOUBLE DOOR LOCK ECU - BATTERY AND BODY GROUND)

  1. B132940E01
    Disconnect the P34 ECU connector.

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

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    +B (P34-1) - Body ground
    		 Always
    		 10 to 14 V
    CPUB (P34-7) - Body ground
    		 Always
    		 10 to 14 V

    Standard resistance:
    Tester Connection
    		 Specified Condition
    GND (P34-14) - Body ground
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3. CHECK COMMUNICATION LINE

  1. B133468E01
    Disconnect the P34 and P33 ECU connectors.

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

    Standard resistance:
    Tester Connection
    		 Specified Condition
    MPX1 (P34-9) - MPX1 (P33-27)
    		 Below 1 Ω
    MPX (P34-9) - Body ground
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE DOUBLE DOOR LOCK ECU


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