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Key Unlock Warning Switch Circuit

WARNING: This page is about a different car, the 2000 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Key unlock warning switch is built into ignition key cylinder. Turn ignition off. Disconnect key unlock warning switch connector. Using an ohmmeter, check continuity between key unlock warning switch terminals. With key inserted (switch on), continuity should exist. With key removed (switch off), continuity should not exist. If continuity is as specified, go to next step. If continuity is not as specified, replace key unlock warning switch.
  2. Check circuits for faults between key unlock warning switch, anti-theft ECU and body ground. See WIRING DIAGRAMS . Repair or replace as necessary. If circuits are okay, check anti-theft ECU pin voltages. See ANTI-THEFT ECU PIN VOLTAGE TESTS  under COMPONENT TESTS. Replace components as necessary and retest system operation. Proceed to next test listed in SYMPTOM DIAGNOSIS  table under TROUBLE SHOOTING.
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