Self-Diagnostic System: Pre-Check
WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2002 Lexus RX 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 immobilizer on this vehicle. Data of the immobilizer or DTC can read from the DLC3 of the vehicle. When a trouble occurs on immobilizer, malfunction indicator light (MIL) does not light on but DTC inspection is performed. Therefore when there seems to be a trouble on immobilizer, use a 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 table.INSPECTING DLC3
Tester Connection Condition Specified Condition 7 (Bus Line) - 5 (Signal Ground) During Communication Pulse Generation 4 (Chassis Ground) - Body Always 1 Ω Or Less 5 (Signal Ground) - Body Always 1 Ω Or Less 16 (B+) - Body Always 9-14 V - 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, so consult the tool's instruction manual.
- Inspect Diagnosis
See RETRIEVING DIAGNOSTIC TROUBLE CODES and CLEARING DIAGNOSTIC TROUBLE CODES .