2007 Lexus RX 400h won't start

Starting Problem # 1: Engine Won't Crank At All

Scenario: You turn the key, but nothing happens: And by nothing, we mean there is no dash light, no sound, nada. The first thing you should do in this case is to pop the hood and check the battery. Either the battery is completely dead or there's a wiring problem in the starting system. Try jump-starting the battery. If that doesn't work, you'll probably have to call for assistance.

Scenario: When you turn the key, you hear a rapid clicking sound, and the dash lights dim. This is your classic low-battery symptom. Jump-starting the battery should get the engine to start.However, if you keep experiencing this problem, you could have a bad battery or alternator, or it could be some­thing as simple as a loose alternator belt. Take your car to a mechanic just as soon as you can.

Scenario: When you turn the key, the lights on the dash come on, but you don't hear anything. Make sure you have the shift selector all the way in park. Move it out of park and then back, or try starting it with the shifter in neutral. If your car has a manual transmission, make sure you have the clutch pressed all the way to the floor. If that doesn't help, you can try jump-starting the battery, but it probably won't work. There's a good chance your car has a bad starter or a problem in the starting circuit. That could mean a prob­lem in the ignition switch, neutral safety switch or starter sole­noid.

Scenario: The dash lights come on when you turn the key, and then go right out, and the engine doesn't crank when you turn the key to start, But, the lights slowly come back on when you release the key. This is another classic: the bad battery connection. When you turn the key to start, the starter pulls so much current that it breaks the connection. Then, when you release the key, the connection slowly comes back. The connection provides enough power to turn the dash lights on, but not enough to crank the starter. Cleaning and tightening the battery terminals may fix this prob­lem.

Scenario: When you turn the key, you hear a single, hard clunk. Turn the headlights on and try again. Do the lights dim slightly when you turn the key? If so, you probably have a bad starter or a seized engine. If the headlights don't dim at all, or just barely dim, there may be a connection problem between the starter solenoid and the starter itself.

Scenario: When you turn the key, you hear a loud, scraping or grinding sound like metal on metal. The starter drive is bad, or the ring gear on the flywheel damaged, or both. You may get the starter to engage if you try turning the key a couple of times, but let go of the key right away if you hear the noise again. If the car does start, you should drive it right over to local repair shop and have the problem fixed.

Starting Problem #2: Engine Cranks but It Won't Start

Scenario: The engine seems to crank normally, but the engine doesn't even sound as if it's trying to start. Is there gas in the tank? Gas gauges are notoriously inaccurate. If you have to move your head to one side to get the needle to move off empty, try adding some gas to the tank.

Scenario: When you first turn the key on, you don't hear the fuel pump run. In cars with electronic fuel injection, you should hear a light hum a few seconds from around the fuel tank. That's the electric fuel pump running. If you don't hear the fuel pump run for a couple seconds when you first turn the key on, try cranking the engine until the oil light goes out. That may start the pump running and allow the engine to start.

Scenario: The engine cranks normally, and it sounds like it wants to start, but it won't. You may have flooded the engine. Hold the gas floor and try again. (Let the gas pedal up when it finally starts). If it's raining out, the ignition system may be wet.

Scenario: The engine cranks unevenly in a repetitive-sounding pattern. You may have a bad timing chain or timing belt. Call a tow truck and have it towed to the repair shop.

Starting Problem # 3: Engine Starts but It Shuts Off

Scenario: The engine starts right up, but shuts off as soon as you release the key. This is the classic symptom of a bad ignition switch. A new switch should fix it.

Scenario: The engine starts and runs, but when you put the transmission in gear, the car lurches and the engine shuts off. The converter clutch in the transmission torque converter probably is engaging when it shouldn't. On some cars, you can bypass this by disconnecting the torque converter clutch solenoid; but unless you know which wire to pull, forget about it. Call for assistance.

Scenario: The engine starts and runs, but seems to idle slowly and stalls when you come to a stop. This probably is a fast idle problem. When the engine is cold, it's supposed to idle a little faster than normal to keep the engine running. You may be able to drive using two feet until the engine warms up: one on the gas to hold the idle up a little and the other for the brake. However, don't keep driving it this way. Take your car to your repair shop just as soon as you