Self-Diagnostic System: Pre-Check
WARNING: This page is about a different car, the 2003 Lexus IS 300 and 2002 Lexus IS 300. 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 this vehicle. Data of the immobilizer or DTC can be read from the DLC3 of the vehicle. When a trouble occurs on the immobilizer, check that the engine warning light does not light up but DTC inspection is performed. When there seems to be trouble with the immobilizer, use the hand-held tester to check and trouble shoot it. See Fig 1.
- Check 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 table.NOTE: If your display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the hand-held tester to DLC3, turned the ignition switch ON and operated the hand-held tester, there is a problem on the vehicle side or tool side. If communication is normal when the tool is connected to another vehicle, inspect 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.INSPECTING DLC3
Terminal No. Connection/Voltage Or Resistance Condition 7 Bus Line/Pulse Generation During Transmission 4 Chassis Ground - Body Ground/1 Ohm Or Less Always 16 Battery Positive - Body Ground/9-14 Volts Always
- Inspect Diagnosis (Normal Mode)
See RETRIEVING DIAGNOSTIC TROUBLE CODES and CLEARING DIAGNOSTIC TROUBLE CODES .