Self-Diagnostic System: Pre-Check
WARNING: This page is about a different car, the 2002 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
- Diagnosis System
- The engine control module (ECM) controls the function of the immobilizer on the vehicle. Data of the immobilizer or diagnostic trouble code (DTC) can be read in the data link connector No. 3 (DLC3) of the vehicle. When a trouble occurs in the immobilizer, the malfunction indicator lamp (MIL) does not come on but the DTC inspection is performed. Therefore when there seems to be trouble with the immobilizer, use the LEXUS hand-held tester to check and trouble shoot it. See Fig 1.
- Inspect the DLC3. 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. See CONNECTOR IDENTIFICATION . See INSPECTING DLC3 CONDITION table.INSPECTING DLC3 CONDITION
Tester Connection Condition Specified Condition 7 (SIL) - 5 (SG) During Communication Pulse Generation 4 (CG) - Body Always 1 Ohm Or Less 5 (SG) - Body Always 1 Ohm Or Less 16 (B+) - Body Always 9-14 Volts
NOTE: If your display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the OBD II scan tool or hand-held tester to DLC3, turned the ignition switch ON and operated the scan tool, there is a problem on the vehicle side or tool side. If communication is normal when the tool is connected to another vehicle, inspect the 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. - Diagnosis Inspection - See RETRIEVING DIAGNOSTIC TROUBLE CODES and CLEARING DIAGNOSTIC TROUBLE CODES .