LS400 Theft Deterrent Key Unlock Warning Switch Circuit Test
- Turn ignition off. Disconnect theft deterrent ECU connectors. Theft deterrent ECU is located under left side of dash, above junction block No. 1. Ensure ignition key is in ignition switch.
- Using a DVOM, check for continuity between theft deterrent ECU harness terminal A6 and ground. See Figure. If continuity is not present, check for short or open circuit in key unlock warning switch circuit. If continuity is present, replace theft deterrent ECU, and retest system.