Section 901 (Engine Immobilizer System - Diagnosis): Pre-Check

1. Description
   1. The ECM controls the function of the immobilizer system on the vehicle.

      Data of the immobilizer system and the Diagnostic Trouble Code (DTC) can be read in the Data Link Connector 3 (DLC3) of the vehicle. When a malfunction occurs in the immobilizer system, even though the security indicator lamp does not come on, DTCs can be checked.

      Therefore, when the immobilizer system seems to be malfunctioning, use the hand-held tester to check for a malfunction and repair it.

2. Inspect the DLC3.

   The vehicle's ECM uses the ISO 9141-2 communication protocol. The terminal arrangement of the DLC3 complies with the SAE J1962 and matches the ISO 9141-2 format.

   Fig 1: Identifying Terminals Of DLC3

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   Standard: 

   Fig 2: DLC3 Conditions Chart

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   HINT:

   If the screen displays "UNABLE TO CONNECT TO VEHICLE" after you have connected the cable of the hand-held tester to the DLC3, turned the ignition switch ON and used the hand-held tester, the problem may be on the vehicle side or the tester side.

   • 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, so consult the Service Department listed in the tester's instruction manual.

1. Check for DTCs.
   1. Connect the hand-held tester to the DLC 3.
      Fig 3: Connecting Hand-Held Tester To DLC 3

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   2. Turn the ignition switch to the ON position.
   3. Read the DTCs by following the prompts on the tester screen.

   HINT:

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

2. Clear the DTCs from memory.
   1. Connect the hand-held tester to the DLC 3.
   2. Turn the ignition switch to the ON position.
   3. Erase the DTCs by following the prompts on the tester screen.

   HINT:

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

HINT:

Perform this procedure when a malfunction occurs in communication between ECM and transponder kev ECU, and communication line.

Fig 4: Identifying Normal Code And Malfunction Code

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1. Check for DTCs.
   1. Using SST check wire, connect terminals TC and CG of the DLC3.
      Fig 5: Connecting Terminals TC & CG

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   2. Turn the ignition switch to the ON position.

      SST 09843-18040

   3. Read the DTCs from the blinking of the check engine indicator light.
2. Clear the DTCs from memory.
   1. Turn the ignition switch OFF.
   2. Disconnect the battery terminals or EFI fuse.
   3. Connect the battery terminals or EFI fuse, and then turn the ignition switch to the ON position.
   4. Check that the normal code is indicated after connecting the fuse.

Fig 6: Identifying MIL Light

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HINT:

Using the DATA LIST displayed on the hand-held tester, you can read the value of the switch, sensor, actuator, etc. without parts removal. Reading the DATA LIST as the first step of troubleshooting is one way to shorten the labor 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 

   Fig 7: Transponder Key ECU Chart (1 Of 2)

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   Fig 8: Transponder Key ECU Chart (2 Of 2)

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*2: Diagnostic Note

• YES indicates that the registration of the ECU communication ID for the ECM and the transponder key ECU has been completed.
• NO indicates that the registration of the ECU communication ID for the ECM and the transponder key ECU has not been completed.

*1: Diagnostic Note

• If the engine does not start using the registered key while the display on the hand-held tester shows "SUPPORT", there may be a problem with the ECM and the transponder key ECU.
• If the engine does not start using the registered key while the display on the hand-held tester shows "NON SUP", there may be a problem with the transponder key ECU.

HINT:

Performing the ACTIVE TEST using the hand-held tester allows you to operate the relay, VSV, actuator, etc. without parts removal. Performing the ACTIVE TEST as the first step of troubleshooting is one way to shorten the labor time.

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.

   Transponder key ECU 

   Fig 9: Transponder Key ECU Details Chart

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