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DTC B1262: A/C ECU Communication Stop: Procedure

  1. CHECK FUSE (A/C) 
    1. Remove the A/C fuse from the main body ECU LH (cowl side junction block LH).
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A/C fuse Always Below 1 Ω

    NG → REPLACE FUSE (A/C) 

    OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY AND BODY GROUND) 
    1. Disconnect the J58 connector.
      Fig 1: Identifying J58 Connector Terminals
      GTY283207Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage and resistance according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      J58-1 (B) - Body ground Always 11 to 14 V

      Standard Resistance

      Tester Connection Condition Specified Condition
      J58-20 (GND) - Body ground Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to A/C Amplifier)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (A/C AMPLIFIER - BATTERY AND BODY GROUND) 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (COMMUNICATION LINE) 
    1. Disconnect the J58, J34 and J76 connectors.
      Fig 2: J58, J34 And J76 Connectors
      GTY358483Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      J58-31 (MPX-) - J34-6 (MPX+) Always Below 1 Ω
      J58-30 (MPX+) - J76-13 (MPI2) Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to A/C Amplifier)
      *2 Front view of wire harness connector
      (to Combination Meter Assembly)
      *3 Front view of wire harness connector
      (to Gateway ECU)
      - -

    NG → REPLACE HARNESS OR CONNECTOR 

    OK → See step   4 

  4. REPLACE A/C AMPLIFIER ASSEMBLY. Refer to  REMOVAL