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Section 249 (Engine Immobilizer System - Diagnostics): Pre-Check

WARNING: This page is about a different car, the 2002 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
  1. Diagnosis System  :
    1. Description

      ECM controls the function of immobilizer on this vehicle. Data of the immobilizer or DTC can be read form DLC3 of the vehicle. When trouble occurs in immobilizer system, the check engine warning light does not light up but DTC inspection is performed.

      Therefore when there seems to be trouble in immobilizer system, use the TOYOTA hand-held tester or SST to check and troubleshoot it.

      Fig 1: Connecting Scan Tool To DLC3
      G01119424Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. NOTE:

      If your display shows "UNABLE TO CONNECT TO VEHICLE" when you have connected the cable of the hand-held tester to DLC3, turned the ignition switch ON and operated the hand-held tester, there is a problem on the vehicle side or tool side.

      • If communication is normal when the tool is connected to another vehicle, inspect DLC3 on the original vehicle.
      • If communication is still not possible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.
      Fig 2: Identifying Data Link Connector DLC3 Terminals
      G01119425Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 3: DLC3 Terminal Specifications
      G01119426Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check the DLC3.

      The vehicle's ECM uses ISO 14230 for communication. The terminal arrangement of DLC3 complies with SAE J1962 and matches the ISO 14230 format.

  2. Inspect Diagnosis (Normal Mode)  :
      NOTE: TOYOTA hand-held tester only, when the diagnosis system is switched from normal mode to check mode, it erases all DTCs and freeze frame data recorded in normal mode. So before switching modes, always check the DTCs and freeze frame data, and note them down.
    1. Check the DTC using TOYOTA hand-held tester.
      1. Prepare the TOYOTA hand-held tester.
      2. Connect the TOYOTA hand-held tester to DLC3.
      3. Turn the ignition switch ON and push the TOYOTA hand-held tester main switch ON.
        4. NOTE: As an example, the blinking patterns for codes; normal, 12 and 99 are shown.

        In the event of 2 or more malfunction codes, indication will begin from the smaller numbered code and continue in order to the larger numbered code.

        Fig 4: Displaying Code Normal
        G01119427Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        Fig 5: Displaying Codes 12 & 99
        G01119428Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Use the hand-held tester to check the DTCs and freeze frame data, note them down. (For operating instructions, see the TOYOTA hand-held tester instruction book.)
      5. See DIAGNOSTIC TROUBLE CODE CHART  to confirm the details of the DTCs.
      6. When DTC 99 is output, there is a trouble in the immobilizer system. Start troubleshooting referring to PROBLEM SYMPTOMS  table.
      7. After completing the check, disconnect terminals No. 13 (TC) and No. 4 (CG) and turn off the display. See Fig 2.
    2. Clear the DTC.

    The following operations will erase the DTCs and freeze frame data.

    1. Operating the OBD II scan tool (complying with SAE J1978) or TOYOTA hand-held tester to erase the codes (See the OBD II scan tool's instruction book for operating instructions.).
    2. Disconnecting the battery terminals or EFI fuse.
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