2018-2025 Lexus LS500 Starter Motor: A Guide to High-Stakes No-Start Diagnosis

Diagnosing a 2018-2025 Lexus LS500 That Won't Start

A no-start condition in a Lexus LS500 can be stressful, especially when you consider the potential repair costs. While the starter motor can fail, it's critical to diagnose the problem correctly, as other issues can present similar symptoms. The most common reasons for a modern Lexus not to start are a dead battery, a faulty alternator, or the starter itself.

Symptoms of a Failing Starter

Listen carefully when you try to start the car. The sounds it makes (or doesn't make) are your best clues.

• Single, Loud Click: You press the start button, and all you hear is one solid 'CLICK'. This often means the starter's solenoid is engaging, but the motor itself isn't turning the engine. This points strongly toward a bad starter motor.
• Rapid Clicking/Chattering: A fast series of clicks is a classic sign of a weak or dead battery. The starter is trying to engage but doesn't have enough power, causing the solenoid to rapidly open and close. Always test the battery before condemning the starter.
🎬 Watch: The #1 mistake people make when their Lexus won't start.
• Whirring or Grinding Noise: If you hear a high-pitched whirring or a harsh grinding sound when you attempt to start the engine, it can indicate a problem with the starter's gear. The motor might be spinning, but the gear is either not engaging the flywheel correctly or is damaged. Continuing to try and start the car can damage the flywheel, leading to a much more expensive repair.
• No Sound at All: If the dashboard lights up but you hear nothing, the problem could be the starter, but it could also be an issue with the ignition switch, a starter relay, or the vehicle's anti-theft system.
• Smoke or Burning Smell: Smoke or a burning smell from under the hood when trying to start the car can be a sign of an electrical short in the starter motor. This is a serious symptom that requires immediate attention.

Known Issues, Recalls, and TSBs for the LS500 Starting System

While there are no recalls specifically for the starter motor on the 2018-2025 LS500, there are other critical issues that can cause a no-start condition.

V35A-FTS Engine Debris Recall

A significant recall was issued for the 3.5L twin-turbo V6 (V35A-FTS) engine concerning machining debris that may not have been cleared during manufacturing. This debris can lead to main bearing failure, which can cause the engine to knock, run rough, or fail to start entirely. If your LS500 is experiencing a no-start or has developed a knocking sound, it is crucial to have a Lexus dealer check if your vehicle is affected by this campaign before proceeding with any other repairs.

Other Related Recalls

Some 2018-2020 LS500 models were also included in a large-scale recall for a failing low-pressure fuel pump inside the fuel tank. A faulty fuel pump 🎬 See this TSB info for Lexus models with hard start issues. will prevent the engine from starting, even if the starter is cranking it normally. Additionally, some early 2018 models were recalled for an ECU issue with the stop/start system that could cause the engine to stall.

Buying a Used LS500 Starter Motor

Given the extremely high labor cost to replace this part, choosing a quality replacement is essential to avoid doing the job twice. This makes a low-mileage, used OEM starter an excellent value proposition.

• Why Used OEM?: The original factory starter, likely made by Denso, is built to Lexus's high-quality standards. Many new aftermarket starters, especially cheaper ones, may use lower-quality materials that can lead to premature failure. Considering the labor involved, the reliability of a genuine OEM part, even a used one, is a significant advantage.
• What to Inspect: When buying a used starter, visually inspect it for any cracks in the housing or signs of heat damage. Check that the electrical terminals are clean and not corroded. Most importantly, verify the part number is 28100-70080.
• Mileage Concerns: Starters on modern Toyota and Lexus vehicles are very durable, often lasting 100,000 to 150,000 miles. A used starter from a low-mileage (e.g., under 60,000 miles) wrecked vehicle is likely to have years of reliable service left and represents a fantastic value.

LS500 Starter Motor Replacement

Replacing the starter on a 2018-2025 Lexus LS500 is a very difficult and labor-intensive job, which is reflected in the high cost.

Cost of Replacement

The cost is dominated by labor due to the starter's poor accessibility.

Installation Procedure Notes

This is not a recommended DIY job for a beginner or even an intermediate mechanic.

• Location: The starter is located on the passenger side of the vehicle, underneath the engine. Access requires safely lifting the vehicle and removing underbody splash shields.
• Disconnect the Battery: This is the absolute first step. Failure to disconnect the negative battery terminal can lead to dangerous electrical shorts and damage to the vehicle's electronics.
• The Top Bolt: The primary difficulty lies in accessing the top mounting bolt. A video from a mechanic shows that it is extremely hard to reach. Using a straight extension is not possible; a swivel socket or universal joint is required. The mechanic warns to be extremely careful not to strip this bolt.
🎬 Watch: A mechanic shows the difficult LS500 starter replacement process.
• Consequences of a Mistake: Stripping the top bolt would be a disaster, likely requiring the removal of the entire exhaust system, including the catalytic converter, just to gain access to fix it. This is why professional installation is strongly recommended.

Frequently Asked Questions (FAQ)