Key Unlock Warning System
WARNING: This page is about a different car, the 2003 Lexus ES 300 and 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
- Verify customer problem. Perform customer problem analysis check (key unlock warning system). See Fig 1.
- If key unlock warning buzzer sounds, go to next step. If key unlock warning buzzer does not sound, refer to the following list for possible cause of the malfunction.
- Check unlock warning switch. See UNLOCK WARNING SWITCH CIRCUIT (KEY UNLOCK WARNING SYSTEM) under SYSTEM TESTS.
- Check front door courtesy lamp switch. See DOOR COURTESY SWITCH ASSEMBLY CIRCUIT (FRONT DOOR) under SYSTEM TESTS.
- Check inputs to multiplex body ECU. See MULTIPLEX BODY COMPUTER ASSEMBLY under TERMINALS OF ECU (KEY UNLOCK WARNING SYSTEM) under PIN VOLTAGE CHARTS.
- Check combination meter. See INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.
- Check wiring. For key unlock warning system wiring, see POWER DOOR LOCKS under SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
- Perform trouble shooting in the following method, depending on the malfunction symptom.
- Perform pre-check. See KEY UNLOCK WARNING SYSTEM PRE-CHECK under SELF-DIAGNOSTIC SYSTEM. Inspection with hand-held tester (ECU Data Monitor) and hand-held tester (Active Test).
- Check inputs to multiplex body ECU. See MULTIPLEX BODY COMPUTER ASSEMBLY under TERMINALS OF ECU (KEY UNLOCK WARNING SYSTEM) under PIN VOLTAGE CHARTS.