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Lexus Won’t Start But Has Power – What Could Be Wrong?

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If your Lexus won't start, but you have power, there are a few things that could be wrong. However, it can be tough to pinpoint this issue on your own. That's why we have taken the time to research to help solve this frustrating problem!

If your Lexus won't start but has power to its electrical components, it could be due to the following:

  • Low Battery
  • Corroded Battery Terminals
  • Loose Battery Cables
  • Failing Engine Computer
  • Bad Starter Motor
  • Damaged Ignition Switch
  • Faulty Starter Solenoid
  • Failing Starter Relay
  • Worn Spark Plugs
  • Faulty Fuel Pump
  • Malfunctioning Immobilizer
  • Failing Engine

We get it; this list can be intimidating. But, don't worry; we will take a closer look at each of these components to help you understand the warning signs of them failing. In addition, we will take a closer look at how to reset your Lexus ECU, so read on!

Lexus UX crossover in the parking lot of a modern office building, Lexus Won't Start But Has Power - What Could Be Wrong?

Lexus Won't Start But Has Power - What Could Be Wrong?

It's one thing if your car has no power and won't start, but what does it mean if it still has power? The Lexus brand is excellent, but it is tough to get to your destination when your car doesn't start.

If your Lexus is suddenly not starting, but you have power to all its electrical components, it's essential to do some detective work to determine the cause. Here are some common culprits and their warning signs:

Lexus RC F Sport on the front of mountain

Low Battery

A low battery will still show you have power, but it may not have enough juice to start your Lexus. The battery's voltage drops below the minimum operating range, causing a power drain.

The battery can be drained if you leave your headlights on overnight or even if you have a faulty interior light! A low-voltage reading will trigger a warning message in your instrument cluster and a service alert to appear on your dash.

You will need to check your battery voltage and have it charged. This may fix the problem, or it may mean you need a new battery.

Corroded Battery Terminals

If your battery terminals are corroded or corrosion on the metal surrounding the terminals, it can cause a voltage drop that will prevent your Lexus from starting.

The corrosion needs to be cleaned off with baking soda and water before being checked by a mechanic. If you don't clean off the corrosion, you might continue having this problem.

Loose Battery Cables

If the battery cables are loose, it will create a poor connection and lead to a voltage drop.

The cables can become loose over time if they're not adequately tightened or vibrate loose. You will need to tighten the cables using a wrench.

Failing Engine Computer

The ECU won't control your vehicle correctly if the engine computer fails. One sign of a failing ECU is that your car will start but die soon afterward.

The ECU may also experience a power interruption, causing the engine to stall.

Having a professional diagnose this issue for you is highly recommended. It would help if you also had them check all electrical components to make sure they are working as they should.

Bad Starter Motor

The starter motor of car

If the starter motor is bad, it won't turn the engine over and start your car.

The starter motor may make a grinding noise when you try to start your car, or it may not even turn on at all. You should take your car in for repairs if you suspect this is the problem.

Damaged Ignition Switch

If the ignition switch is damaged, it can prevent your car from starting.

The most common sign of a damaged ignition switch is when the car won't start, but all electrical components turn on.

You may also notice that the key doesn't want to turn in the ignition or lock your steering wheel.

Faulty Starter Solenoid

The starter solenoid assists the starter motor to turn the engine over and start your car. If this component fails, it can prevent your car from starting up at all.

One sign that your starter solenoid isn't working properly is if you hear a clicking or grinding noise when you turn the key.

Failing Starter Relay

If the starter relay fails, it won't send power to the starter motor. This will prevent your car from starting.

One sign that the starter relay is bad is if the engine cranks but doesn't start. This means that the starter isn't getting an electrical signal from the battery to the starter. So no matter how many times you try and start your Lexus, it won't start.

Worn Spark Plugs

If the plugs are worn, they won't ignite the fuel properly, and your car will not start.

Sometimes, you may notice that your car is harder to start than normal or that it takes a few tries before it finally starts. However, if the spark plugs aren't changed, you will eventually get in a position where your Lexus won't start at all.

If you haven't had your spark plugs changed in 30,000-40,000 miles, then this is a tell-tale sign that your spark plugs are worn.

Faulty Fuel Pump

If the fuel pump is bad, it won't push gasoline from the tank to the engine.

One sign that the fuel pump is a whining noise coming from the fuel tank. Fuel pumps are one component that will keep your car from starting, but you will still have power to the car.

Malfunctioning Immobilizer System

If the immobilizer system malfunctions, it won't send a signal that allows your Lexus to start. The immobilizer is a security system, and if it is faulty, it will tell the car that there is a security breach and won't let you start the car.

If you are having trouble locking and unlocking your Lexus, then this is a warning sign your immobilizer system is bad.

Failing Engine

In the worst-case scenario, if the engine fails, it will prevent your car from starting. One sign that the engine is failing is if you hear a knocking noise when trying to start your car.

You may also experience a loss of power, or the car may just shut off while you're driving it. If you are experiencing any of these symptoms, it is best to take your car to a mechanic to have it diagnosed.

No matter the problem, if your Lexus won't start, it can be a simple fix, or you should take it in for repairs. A professional can help you determine what is wrong with your car and how to fix it.

How do I know if my starter relay has power?

If you know where to find the starter relay on your Lexus, you can test to see if it has power. First, remove the relay cover and use a test light or voltmeter to check for power. There should be power when you turn the key in the ignition. If there is no power, the starter relay is wrong and should be replaced.

How do I reset my Lexus computer?

If you need to reset your Lexus computer, you have some options. Let's take a look at each below:

Disconnect Battery

The most common way to reset your Lexus computer is by disconnecting the battery. This will clear all the codes from the computer and allow it to start fresh.

Use a Programmer

If you have a code reader, you can reset the ECU. In addition, auto stores such as O'reilly's and Autozone will let you use theirs for free. Finally, you can plug in the code programmer and reset the ECU.

In addition, you can take it to a mechanic and have them do it. Depending on the mechanic, they will do it at no cost or charge you a small fee.

Remove ETCS and EFI Fuses

Lastly, follow these instructions to reset your ECU:

  1. To remove these two fuses, you will need to locate the fuse box under the hood of your car.
  2. Once, located use pliers to remove the EFI and ETCS fuses (use the fuse diagram on the fuse box for help).
  3. Now that the fuses are removed, wait 5 minutes before putting them back in.

What does an ECU reset do?

Doing an ECU reset will clear all of the long-term memory from the car computer. In addition, doing this will delete any codes that your car is throwing. As a result, your vehicle computer will go to its default factory settings.

How much is a starter for a Lexus?

The cost to get a starter replaced in a Lexus can vary significantly. It will depend on whether you plan to do the job yourself or have a Lexus mechanic do it. With that being said, the price can range from $300 to as much as $1,200.

Keep in mind; it will also depend on the year of your Lexus and what model you have. The best thing to do is get the VIN to your Lexus and contact a Lexus mechanic or the Lexus dealer to get a quote.

Car engine start button black and white close-up with blurred background

In Conclusion

If your Lexus won't start, it doesn't mean you have a bad vehicle. It just means that it is made with mechanical parts and doesn't last forever. If you have power, but the vehicle won't start, then start by checking the battery.

If the battery voltage is sufficient, the terminals are clean, and the cables are tight, check the starter next. From there, your best bet is to contact a Lexus certified mechanic for help.

For more maintenance guides like this one, then you should read:

Rattling Noise In Car When Accelerating—What Could Be Wrong?

My Car Won't Start But It Clicks [5 Potential Causes]

Antifreeze Leaking From Car – What Could Be Wrong?