Engine Immobilizer System - Diagnostics: Pre-Check

DIAGNOSIS SYSTEM
1. Description
  Engine ECU controls the function of immobilizer on this vehicle.
  
  Fig 1: DTC Can Be Read From DLC3
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Data of the immobilizer or Diagnostic Trouble Code (DTC) can be read from the Data Link Connector 3 (DLC3) of the vehicle. When a trouble occurs in the immobilizer, Malfunction Indicator Lamp (MIL) does not light up but the DTC inspection is performed. Therefore when there seems to be a trouble with immobilizer, use a hand-held tester or SST (diagnosis check wire No. 2) to check and troubleshoot it.
2. Inspect the DLC3.
  
  Fig 2: Connecting Hand-Held Tester To DLC3
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  The vehicle's ECM uses ISO 9141-2 for communication. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.
  
  Fig 3: Identifying DLC3
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  NOTE: If your display shows "UNABLE TO CONNECT TO VEHICLE" when you have connected the cable of the hand-held tester to the DLC3, turned the ignition switch ON and operated the hand-held tester, there is a problem on the vehicle side or tool side.
  - If the communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
  - If the communication is still impossible 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.
INSPECT DIAGNOSIS
1. Using hand-held tester:
  Check the DTC.
  
  NOTE: Hand-held tester only:
  When the diagnosis system is switched from the normal mode to the check mode, all the DTCs and freeze frame data recorded in the normal mode will be erased. So before switching the modes, always check the DTCs and freeze frame data, and note them down.
  1. Prepare the hand-held tester.
    
    Fig 4: Connecting Hand-Held Tester To DLC3 Under Instrument Panel Lower Pad
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Connect the hand-held tester to the DLC3 under the instrument panel lower pad.
  3. Turn the ignition switch ON and push the hand-held tester switch ON.
  4. Use the hand-held tester to check the DTCs and freeze frame data; note them down. (For operating instructions, see the hand-held tester instruction book.)
  5. See DIAGNOSTIC TROUBLE CODE CHART to confirm the details of the DTCs.
2. Clear the DTC.
  The following procedures will erase the DTCs and freeze frame data.
  1. Operating the hand-held tester to erase the codes. (See the hand-held tester instruction book for operating instructions.)
  2. Disconnecting the battery terminals or EFI1 fuse.