2021 Lexus IS300 Cruise Control Isn't Working

Fixing Cruise Control Issues in the 2021 Lexus IS300

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Reviewed by
Andrew Hajjar
Written by RepairPal Car Genius
Updated January 14, 2025
0%
30% chance it's the
Sensor
0%
25% chance it's the
Control Module
0%
25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a 2021 Lexus IS300 cruise control isn't working are failed control module, sensor or switch issues, or throttle actuation problems.
  • Sensor: A faulty or malfunctioning sensor can lead to incorrect readings, causing issues with engine performance or other systems relying on accurate data.
  • Control Module: A faulty control module can lead to erratic vehicle behavior or failure of various electronic systems due to improper signal processing.
  • Throttle: A faulty throttle body or a defective accelerator pedal position sensor may be causing inconsistent throttle response.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2021 Lexus IS300 cruise control isn't working?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

When the vehicle speed sensor fails or the wiring harness prevents signal transmission, the speedometer is the first thing that will stop functioning properly. This can be an intermittent issue where the speedometer only works occasionally, the speedometer may cease all function, or the speedometer may read erratically or incorrectly. Also, the traction control and anti lock brake warning lights specific to each vehicle may be illuminated, depending on the design of those systems. You may notice the vehicle hesitate to accelerate, cruise control will not function properly, and the vehicle may not shift properly through all of the gears.

In the event that a wheel speed sensor fails, the ABS, traction control system (TCS) and manufacturer specific stability control system lights will illuminate, informing the driver that the systems are disabled. The vehicle will be more prone to tire slip, and normal driving patterns may need to be adjusted to correct for the loss of computer control. On older vehicle's, the speedometer can be affected, causing illumination of the check engine light as well.

The cruise control switch can cause complete failure of the cruise control feature, but in a lucky scenario only partial functionality will be lost. This means that the cruise control may come on, but that it will not increase in speed automatically, or the cancel button does not work leading the driver to cancel cruise control with the foot brake. In some vehicles, the cruise control light may illuminate, or a warning message may be displayed due to lack of functionality.

What steps should I take to diagnose the cruise control issue in my 2021 Lexus IS300?

When diagnosing a cruise control issue in your 2021 Lexus IS300, it's essential to adopt a systematic approach that begins with the simplest potential problems before moving on to more complex diagnostics. Start by checking the cruise control fuse in the fuse box, as a blown fuse can often be the culprit behind malfunctioning systems. Next, inspect the cruise control buttons on your steering wheel to ensure they are functioning correctly, as faulty buttons can disrupt the system's operation. Following this, verify the speed sensor, which is critical for cruise control functionality; any issues here can significantly impact performance. Utilizing an OBD-II scanner to check for error codes can provide valuable insights into specific problems affecting the cruise control system. Additionally, if your vehicle uses vacuum pressure for cruise control, inspect the vacuum lines for any leaks or damage that could hinder operation. If these steps do not resolve the issue, it may be time to consult a professional mechanic or visit a dealership for a comprehensive inspection and repair. By following this diagnostic approach, you can effectively identify and address the cruise control issue in your Lexus IS300.

What are the common problems that could cause the cruise control to stop working in a 2021 Lexus IS300?

When troubleshooting the cruise control system in a 2021 Lexus IS300, it's essential to understand the common problems that may lead to its malfunction. One prevalent issue is a faulty speed sensor, which can hinder the system's ability to accurately gauge the vehicle's speed, preventing it from engaging or maintaining the desired speed. Additionally, the brake light switch plays a crucial role; if it malfunctions, the cruise control may disengage unexpectedly when the brake pedal is pressed. Another potential culprit is the throttle control system, where a defective throttle position sensor or actuator can disrupt the cruise control's functionality. Electrical problems, such as blown fuses or wiring issues, can also impede the system's operation, as can vacuum leaks that affect the necessary pressure for cruise control to function properly. By identifying and addressing these common issues, you can effectively troubleshoot and restore the cruise control system in your Lexus IS300.

How urgent is it to address the malfunctioning cruise control in a 2021 Lexus IS300?

When dealing with a malfunctioning cruise control in a 2021 Lexus IS300, it is essential to recognize the urgency of the situation. A malfunctioning system not only compromises your safety on the road but can also lead to serious accidents if the vehicle unexpectedly accelerates or fails to maintain speed. Additionally, the inconvenience of a faulty cruise control can detract from your overall driving experience, making long trips more uncomfortable and stressful. Ignoring these symptoms can result in further damage to the vehicle's systems, leading to more extensive repairs and higher costs down the line. Therefore, it is crucial to consult the manufacturer's guidelines or seek advice from a certified mechanic to assess the severity of the issue and take appropriate action promptly. Addressing the malfunction not only ensures your safety but also helps maintain the performance and longevity of your vehicle.

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2021 Lexus IS300 Cruise Control Malfunctions & Solutions