Engine Immobilizer System - Diagnostics: Pre-Check

1. Description
   1. The transponder key ECU controls the vehicle's immobilizer system functions. Immobilizer system data and the 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 immobilizer system even though the security indicator is not illuminated. When the system seems to be malfunctioning, use the hand-held tester to check for malfunctions and perform repairs.
2. Inspect the DLC3.

   The vehicle uses the ISO 15765-4 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.

   TERMINAL DESCRIPTION CHART
   
   

   Symbols (Terminal No.)	Terminal Description	Condition	Specified Condition
   SIL (7) - SG (5)	Bus "+" line	During transmission	Pulse generation
   CG (4) - Body ground	Chassis ground	Always	Below 1 Ω
   SG (5) - Body ground	Signal ground	Always	Below 1 a
   BAT (16) - Body ground	Battery positive	Always	11 to 14V

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

   HINT:

   Connect the cable of the hand-held tester to the DLC3, turn the ignition switch ON and attempt to use the tester. If the screen displays the message UNABLE TO CONNECT TO VEHICLE, there may be a problem either with the vehicle or with the tester.

   • If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle.
   • If communication is still impossible when the tester is connected to another vehicle, the problem may be in the tester itself. Consult the Service Department listed in the tester's instruction manual.
   Fig 1: Identifying DLC3

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Fig 2: Connecting Cable Of Hand-Held Tester To Dlc3

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Inspect the battery voltage.

   Standard: 11 to 14 V 

   If the voltage is below 11 V, replace the battery before proceeding.

1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch ON.
3. Read the DTCs by following the directions on the tester's screen.
   Fig 3: Connecting Hand-Held Tester To DLC3

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Refer to the hand-held tester operator's manual for further details.

1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch ON.
3. Erase the DTCs by following the directions on the tester's screen.

HINT:

Refer to the hand-held tester operator's manual for further details.

HINT:

Using the hand-held tester's DATA LIST allows switch, actuator and other item values to be read without removing any parts. Reading the DATA LIST early in troubleshooting is one way to save time.

1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch ON.
3. Read the DATA LIST according to the display on the tester.

Transponder key ECU assy: 

Fig 4: Identifying Transponder Key ECU DATA List

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Performing the hand-held tester's ACTIVE TEST allows relay, VSV, actuator, and other items to be operated without removing any parts. Performing the ACTIVE TEST early in troubleshooting is one way to save time. The DATA LIST can be displayed during the ACTIVE TEST.

1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch ON.
3. Perform the ACTIVE TEST according to the display on the tester.