1. Immobiliser System (if equipped): 1993 might be on the cusp of widespread immobiliser use. This system prevents the engine from starting unless the correct key is used. Symptoms of an immobiliser problem:
* Key won't turn in the ignition: The key might be stuck or only turn a certain amount.
* No cranking at all: The engine doesn't even try to turn over.
* Dash warning lights: Look for a flashing security light or a different unusual warning light.
If you suspect the immobiliser:
* Try a spare key: If you have a second key, try that. If it works, your original key's transponder chip might be faulty.
* Check the battery in your key: Some keys have batteries for the immobiliser system. A dead battery will prevent the car from starting.
2. Battery:
* Check the battery voltage: Use a multimeter to check the battery's voltage. It should be around 12.6 volts when fully charged. A low voltage will prevent the engine from starting. A completely dead battery will result in nothing happening when you turn the key.
* Check the battery terminals: Corrosion on the terminals can prevent a good connection. Clean them with a wire brush.
3. Starter Motor:
* Listen carefully when turning the key: Do you hear a clicking sound? A single click usually indicates a low battery or a problem with the starter solenoid. Multiple clicks might indicate a problem with the starter motor itself. A complete lack of sound usually points to the battery or a main power cable issue.
4. Ignition System:
* Check the fuses and relays: Look in your owner's manual for the location of the fuse box and check the fuses related to the ignition system.
* Have a mechanic check the ignition switch: A faulty ignition switch can prevent the engine from starting. This is something best diagnosed by a professional.
5. Other Potential Issues (Less Likely):
* Fuel pump: A faulty fuel pump might not deliver fuel to the engine.
* Fuel filter: A clogged fuel filter can restrict fuel flow.
* Engine control module (ECM): Problems with the ECM can prevent the engine from starting.
In short: The "engine lock" is not a physical device, but a combination of security systems and electrical components. Start with the simplest checks (battery, key) and work your way down the list. If you're not comfortable diagnosing these issues yourself, take your Lexus to a qualified mechanic. They'll have the tools and expertise to diagnose the problem quickly and accurately. Remember to mention the year and model of your vehicle (1993 Lexus ES300) to ensure they have the correct information.
