Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1992 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Pretest Inspection
- Open driver's side door. Ensure all other doors are closed. Using ignition key transmitter, lock and unlock doors 10 times within 30 seconds. Within 2 seconds of locking and unlocking doors, press ignition key transmitter button for 10 seconds. Record number of times all doors are locked and unlocked within the 10 seconds.
- If doors lock and unlock once, go to next step. If door locks do not operate, malfunction is in remote system. See TROUBLE SHOOTING for system diagnosis. If doors lock and unlock 2 times, malfunction is in transmitter (transmitter and ROM within ECU are not compatible). Replace transmitter and ROM. If doors lock and unlock 3 times, malfunction is in transmitter. Go to TRANSMITTER BATTERY TEST .
- Close all doors. Disconnect antenna cable from remote door lock ECU. ECU is located on left side of luggage compartment. Insert ignition key (transmitter) into antenna location of ECU.
- Press transmitter button. DO NOT let transmitter come in contact with ECU case (transmitter will be grounded). If all doors lock and unlock, go to next step. If all doors do not lock and unlock, problem is in antenna circuit. Go to ANTENNA CIRCUIT TEST .
- Tune radio to 94.9 FM. While listening to radio, push transmitter button. If noise is heard from radio, malfunction is in remote system. See TROUBLE SHOOTING for system diagnosis. If noise is not heard, inspect transmitter. Go to TRANSMITTER BATTERY TEST .
NOTE:
In some locations, radio broadcast may exist on 94.9 FM. If this occurs, perform inspection using a portable radio in a place indoors free from the influence of FM broadcasts.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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