Dtc B1262 A/C Ecu Communication Stop

Communication System. Lexus Is250, Is220D. Gse20 Ale20
Multiplex Communication. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FUSE (A/C)

CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BATTERY AND BODY GROUND)

CHECK RESISTANCE OF COMMUNICATION LINE

DTC B1262 A/C ECU Communication Stop


DESCRIPTION

  1. This DTC is detected when communication between the air conditioning amplifier (A/C ECU) and gateway ECU stops for more than 10 seconds.

DTC No.
DTC Detection Condition
Trouble Area
B1262
Air conditioning amplifier (A/C ECU) communication stops
  1. Air conditioning amplifier (A/C ECU)
  2. Wire harness

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Multiplex Communication.Multiplex Communication System. Dtc B1262 A/C Ecu Communication Stop


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 B1262, repair the "+B or GND short malfunction of communication bus" DTCs first.
1.CHECK FUSE (A/C)

  1. Remove the A/C 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 (AIR CONDITIONING AMPLIFIER - BATTERY AND BODY GROUND)


    Lexus Is250, Is220D. Gse20 Ale20.Multiplex Communication.Multiplex Communication System. Dtc B1262 A/C Ecu Communication Stop

  1. Disconnect the J58 ECU connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    B (J58-1) - Body ground
    		Always
    		10 to 14 V
    Standard resistance:
    Tester Connection
    		Specified Condition
    GND (J58-20) - Body ground
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK RESISTANCE OF COMMUNICATION LINE


    Lexus Is250, Is220D. Gse20 Ale20.Multiplex Communication.Multiplex Communication System. Dtc B1262 A/C Ecu Communication Stop

  1. Disconnect the J58, A27, J34 and J76 ECU connectors.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    *1MPX- (J58-31) - MPX1 (A27-5)
    		Below 1 Ω
    *2MPX- (J58-31) - MPX+ (J34-6)
    		Below 1 Ω
    MPX+ (J58-30) - MPI2 (J76-13)
    		Below 1 Ω
    HINT:
    1. *1: w/ Adaptive front-lighting system
    2. *2: w/o Adaptive front-lighting system
    Result:
    Result
    		Proceed to
    Both are OK
    		A
    One is OK
    		B
    Both are NG
    		C


B
REPLACE AIR CONDITIONING AMPLIFIER AND REPAIR OR REPLACE HARNESS OR CONNECTOR

C
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY