Dtc B1262 A/C Ecu Communication Stop

Communication System. Lexus Gs430, Gs300. Uzs190 Grs190
Multiplex Communication. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK OPERATION

CHECK WIRE HARNESS (No. 2 AIR CONDITIONING AMPLIFIER ASSEMBLY (A/C ECU) - 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 No. 2 A/C control amplifier (A/C ECU) and gateway ECU stops for more than 10 seconds.

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

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1262 A/C Ecu Communication Stop


INSPECTION PROCEDURE

1.CHECK OPERATION

  1. Check that the A/C switch can operate the A/C normally.

    OK:
    A/C switch can operate A/C normally.


NG
Go to step 2
OK

REPLACE No. 2 AIR CONDITIONING AMPLIFIER ASSEMBLY (A/C ECU)

2.CHECK WIRE HARNESS (No. 2 AIR CONDITIONING AMPLIFIER ASSEMBLY (A/C ECU) - BATTERY AND BODY GROUND)
Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1262 A/C Ecu Communication Stop

  1. Disconnect the L52 ECU connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    L52-21 (IG+) - Body ground
    		Engine switch on (IG)
    		10 to 14 V
    L52-1 (B) - Body ground
    		Always
    		10 to 14 V
    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    L52-20 (GND) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


3.CHECK RESISTANCE OF COMMUNICATION LINE

Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1262 A/C Ecu Communication Stop

  1. Disconnect the L52 ECU connector.

  1. Disconnect the L12 panel connector.

  1. Disconnect the L44 sensor connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    L52-30 (MPX+) - L44-22 (MPX2)
    		Below 1 Ω
    L52-31 (MPX-) - L12-8 (MPX2)
    		Below 1 Ω
    Result:
    Result
    		Proceed to
    Both are OK
    		A
    One is OK
    		B
    Both are NG
    		C


B
REPLACE No. 2 AIR CONDITIONING AMPLIFIER ASSEMBLY AND HARNESS AND CONNECTOR

C
REPAIR OR REPLACE HARNESS AND CONNECTOR
A

REPLACE No. 2 AIR CONDITIONING AMPLIFIER ASSEMBLY (A/C ECU)