Lexus Won’t Start but Has Power: Causes and Simple Fixes

Lexus won’t start but has power for various reasons, such as a failing battery or a damaged starter relay. It can also happen due to an activated theft deterrent system or control unit defects.

Lexus Wont Start

Sometimes the solution is as simple as replacing the key fob battery, but you might need professional help if the engine has a problem. This blog post will help you find what prevents your Lexus from starting and learn how to fix them.

Why Won’t Your Lexus Start but Has Power?

Your Lexus won’t start but has power because of a weak battery or corroded terminals. Problems with the ECU may trigger the anti-theft mechanism and prevent the car from starting. Moreover, issues with the fuel delivery components, starter relay, ground connections, or spark plugs do not let the car start.

  • Weak Battery, Damaged Terminals, or Worn Cables

If your Lexus won’t start clicking noise is heard if there is a car battery or cable problem. You can confirm a problem with the battery if the lights and fans in your Lexus do not turn on. Sometimes the battery drains if you forget to switch off the headlights while parking. In that case, jump starting or charging the battery would solve the problem.

Starter Problem of Lexus

However, you might have a dead battery if the car still does not charge. It usually happens if the battery is too old. These car batteries last 3 to 5 years, but some factors can speed up the process. The dead battery will fail to power the engine, lights, horns, and other accessories. You can confirm it by using an amp meter or multimeter.

Damaged or corroded battery terminals are another reason your Lexus will not start. You can clean the buildup from corrosion or fix the cracks using epoxy. Therefore, the problem with the terminals is a relatively inexpensive one. If you have ruled out the above possibilities, inspect the battery cables. These cables get loose over time because of vibrations. Moreover, they may corrode or get damaged after rodents chew on them.

  • Problems With the Lexus Control Unit

A malfunctioning ECU does not send the necessary signals to the engine components. It explains why Lexus Hybrid won’t start. The control unit gets damaged due to various reasons.


One possibility is malfunctioning sensors that send information to the ECU. The ECU depends on input from these sensors to determine the engine’s working conditions. These sensors include a coolant temperature sensor, crankshaft, and camshaft position sensor. A problem with the fuel delivery system can be linked to ECU because it controls the fuel pump, injectors, and other components.

So in case the fuel system has clogged filters or failing pumps and injectors, the ECU will not deliver fuel to the engine. The ECU connects to the other components through wires and terminals. When these wires get damaged, corroded, or loose, the electric supply disrupts. Similarly, a blown fuse breaks the circuit and prevents the electric supply to the engine.

Lexus rx 350 won’t start clicking noises can also be explained by the ECU’s immobilizer issue. Many modern vehicles have immobilizer systems to prevent unauthorized starting. When these immobilizers, such as an ignition switch and transponder, wear out, the car may not start.

  • Defective Lexus Fuel Delivery System

The Lexus ES 350 won’t start clicking noise if the fuel pump fails to produce the required pressure for pushing fuel into the engine. You can suspect this problem if you have an old Lexus or have been using low-quality fuel.

The substandard fuel gradually damages the pump and other fuel system components. A humming sound from the back of the car usually accompanies the failure of the pump. If the fuel pump seems fine, you can inspect the fuel line to detect clogged components blocking the fuel from flowing. Over time, the fuel filter can become filled with contaminants.

Therefore, a severely clogged filter can restrict flow and prevent the engine from starting.
Moreover, the fuel injectors deliver fuel into the combustion chambers. If these injectors become clogged or fail to open and close, the engine may not obtain the crucial fuel for starting.

These fuel delivery system components clog if the Lexus has contaminated fuel. It may get clogged with water, impurities, or sediment. These problems root in low-quality fuel or additives. Lastly, although it sounds evident if the fuel tank is empty or has a deficient fuel level, the engine won’t start. It’s essential to ensure there is an adequate amount of fuel in the tank.

  • Faulty Lexus Engine Spark Plugs

If your Lexus is 250, push button start problems can occur due to faulty sparking plugs. The plugs produce the spark that initiates the ignition of the fuel in the engine. If these plugs fail, the fuel will not burn, and your Lexus will not start.

These plugs ignite the fuel in each cylinder and are easy to inspect if you suspect damage. You can remove and observe cracks, buildup, or signs of wear. Test them with a multimeter to ensure electric power reaches the combustion chamber even when they look fine. The dashboard lights also indicate problems with the sparking plugs.

The plugs may get damaged due to the following reasons:

  • Carbon, oil, or fuel deposits on the plug electrode, insulator, or firing tip. These deposits lead to reduced engine performance or misfiring. The particles deposit due to an improper air-fuel mixture, faulty valve seals, worn piston rings, or the using low-quality fuel.
  • Excessive heat melts or burns the electrodes, leading to poor performance and misfiring. Incorrect plug heat range, a lean combustion mixture, or inaccurate ignition timing may cause overheating.
  • Contaminants can enter the combustion unit and affect the plug performance. Dirt or debris may interfere with the spark or damage the electrodes.
  • An incorrect electrode gap affects the plug’s performance. If the gap is too large or too small, it can lead to inefficient combustion and misfiring.
  • The electrodes of sparking plugs can erode over time due to the electrical arcing during combustion. It leads to increased voltage requirements.
  • Pre-ignition of the air-fuel mixture. It causes severe damage to the plug, such as electrode melting or erosion.


  • Electrical Issues Due To Faulty Ground Connection

If the Lexus ES 350 won’t start brake pedal is pushed, it might have faulty ground connections. The ground connection is the battery’s negative terminal connected to the body of ES. Similarly, the engine needs the ground connection, so a ground strap connects it to the chassis. This ground connection in your Lexus ES may get damaged by corrosion or rust and cause electrical problems. For instance, you might hear a clicking sound, but the engine will not start.

The noise comes from the starter solenoid because it only requires a low current. However, the starter motor needs a high current, so it will only work with proper grounding.
You can inspect the connectors and cables used for grounding. These include cables from the battery to the car’s body and cables from the body to the engine. Use sandpaper to clean the contacts if you find signs of rust or corrosion.

Moreover, you can use a multimeter to test the grounding in your ES. This conductivity test will confirm why the car won’t start. Set the multimeter for “Ohm” and place the probes against the battery’s negative terminal and metal part of the engine.

Getting a reading close to or equal to zero is best. Then repeat the procedure, but this time place the probes against the battery’s negative terminal and metal part of the chassis.

  • Car Won’t Start Due To Damaged Starter Relay

If there is trouble with the starter relay, Lexus won’t start depress brake won’t work, but it will still have power. When you turn on the ignition switch, the starter motor connects to the crankshaft and makes it rotate.

So when the faulty starter relay fails to power the motor, the engine does not crank. You can test the relay by opening the fuse box with a flat screwdriver. Once the cover is off, ask someone to start the car, and if you hear clicking from the side of the relay, there will be no problem.

You can borrow the starter relay from someone to see if the car cranks. If the car starts, you have a bad starter relay.

How To Fix a Lexus That Does Not Start but Has Power?

To fix a Lexus that does not start but has power, start by cleaning, recharging, or replacing the battery. If you use a key fob, you should replace its battery if damaged. Moreover, you can replace damaged components, such as fuel injectors, pumps, or timing chains.

  • Recharge or Replace the Lexus Battery

The battery could be weak or drained even when your Lexus has power. First, inspect the terminals for corrosion and scrap the buildup with sandpaper. If the terminals are loose, you can tighten them with pliers after disconnecting the cables.

Fix a Lexus Starter Problem

If it still does not work, jump start your car with the help of another vehicle. If the Lexus starts, you can confirm that the Lexus push button start problems are due to a faulty battery. In that case, you can buy a new battery and replace the old one.

  • Fix the Key Fob Control

If you use a key fob, remember to change its battery regularly. Moreover, if you recently dropped the controller on the floor or road, you must replace it. However, if you use traditional keys, insert them fully and turn on the ignition switch.

  • Check Fuel Levels and Repair Faulty Fuel Delivery Parts

First, ensure that your Lexus has an adequate amount of fuel. You can observe the fuel tank if the fuel gauge shows the wrong reading. If filling the fuel does not start the car, clean or replace the fuel filters.

You can remove the filters and use a soft brush and water to clear out the clogging particles. It should make the fuel reach the engine and start your Lexus. However, if the fuel system has other problems, like a faulty fuel pump or injector, you must replace them. You can ask a mechanic to replace these components.

The fuel pump costs around $100 to $500 if you choose an OEM pump. An aftermarket pump would cost less, but you must also consider the labor cost. The injectors cost less, but the labor cost depends on their location inside the Lexus.

  • Replace the Starter Motor or Timing Belt

Depending on the Lexus model, a brand-new starter motor typically ranges from $100 to $500. The expense can vary based on the brand and quality of the motor. You can buy a remanufactured motor for $50 to $300 if it exceeds your budget. If you lack prior experience, you should always hire professionals to replace the motor.

However, if your Lexus does not start due to a faulty timing chain, you should get it replaced. Since the procedures vary from car to car, you should consult the service manual that came with your Lexus.

Starter Relay Issues on Lexus

Are the Reasons for a Lexus Not Starting Similar to a Prius?

Are the reasons for a Lexus not starting similar to a Prius? If you’re experiencing starting issues with your Prius, a comprehensive guide to Prius starting problems can help. However, it’s important to note that while both Lexus and Prius are hybrid vehicles, their internal systems may differ, leading to distinct starting issues. A thorough understanding of the specific model is necessary to troubleshoot the problem effectively.


Now that you know why your Lexus won’t start but has power, you can take a step forward to fix it.

Here’s a summary of this blog post focusing on the main points:

  • A dead or weak battery, faulty cables or ground connection, and starter relay issues prevent Lexus from starting.
  • Damaged ignition plugs in the engine and fuel delivery components do not let the engine start.
  • You can make your Lexus start by restoring the fuel supply to the engine, charging the battery, or resetting the security system.

These diagnosing and fixing steps will help you enjoy the Lexus drives once again.

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