ENGINE IMMOBILISER SYSTEM DIAGNOSIS SYSTEM


  1. DESCRIPTION


    1. Engine immobiliser system data and Diagnostic Trouble Codes (DTCs) can be read through the vehicle's Data Link Connector 3 (DLC3). In some cases, a malfunction may be occurring in the immobiliser system even though the security indicator is not illuminated. When the system seems to be malfunctioning, use the intelligent tester to check for malfunctions and perform repairs.

  2. CHECK DLC3


    1. A01BGTYE16

      The vehicle's ECM uses ISO 9141-2 (Euro-OBD) communication protocol. The terminal arrangement of the DLC3 complies with ISO 15031-03 and matches the ISO 9141-2 format.

      Symbols (Terminal No.) Terminal Description Condition Specified Condition
      SIL (7) - SG (5) Bus "+" line During transmission Pulse generation
      BAT (16) - Body ground Battery positive Always 11 to 14 V
      CG (4) - Body ground Chassis ground Always Below 1 Ω
      SG (5) - Body ground Signal ground Always Below 1 Ω
      CANH (6) - CANL (14) CAN bus line Ignition switch off* 54 to 69 Ω
      CANH (6) - CG (4) HIGH-level CAN bus line Ignition switch off* 200 Ω or higher
      CANL (14) - CG (4) LOW-level CAN bus line Ignition switch off* 200 Ω or higher
      CANH (6) - BAT (16) HIGH-level CAN bus line Ignition switch off* 6 kΩ or higher
      CANL (14) - BAT (16) LOW-level CAN bus line Ignition switch off* 6 kΩ or higher

      Note

      *: Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors.


      • If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.

      Tech Tips

      Connect the cable of the intelligent tester to the DLC3, turn the ignition switch ON and attempt to use the tester. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the tester.

      A01BD31E01

      • If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle.

      • If communication is still not possible when the tester is connected to another vehicle, the problem is probably in the tester itself. Consult the Service Department listed in the tester's instruction manual.