Diesel Data: Automotive Repair

Diagnosis System








ENGINE IMMOBILISER: ENGINE IMMOBILISER SYSTEM (w/ Smart Key System): DIAGNOSIS SYSTEM

DIAGNOSIS SYSTEM

1. DESCRIPTION
(a) The certification ECU controls vehicle's immobiliser system function. Immobiliser 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 immobiliser system even though the security indicator light is off. When the system seems to be malfunctioning, use the Techstream to check for malfunctions and perform repairs.
2. CHECK DLC3





(a) The vehicle's ECU uses ISO 15765-4 for communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.





NOTE: *: Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the Power 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.

(b) Connect the cable of the Techstream to the DLC3, turn the power switch on (IG) and attempt to use the Techstream. If the screen displays a communication error message, a problem exists in the vehicle side or tester side.
HINT:
- If communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
- If communication is still impossible when the tool is connected to another vehicle, the problem is probably in the tool itself. Consult the Service Department listed in the tool's instruction manual.