Lexus LC500h Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Lexus LC500h and How to Fix Them

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Reviewed by
Devin Cabugcal
Written by RepairPal Car Genius
Updated January 14, 2025
0%
30% chance it's the
Sensor
0%
25% chance it's the
Control Module
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25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a Lexus LC500h 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 Lexus LC500h 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.

Troubleshooting Cruise Control Issues in a Lexus LC500h

When troubleshooting cruise control issues in a Lexus LC500h, it's crucial to follow a structured diagnostic approach that prioritizes simpler solutions before tackling more complex problems. Begin by checking for blown fuses, as this is a common and straightforward fix that can often resolve cruise control malfunctions. Next, inspect the brake pedal and throttle body, since any irregularities in these components can significantly impact the cruise control system's performance. Utilizing a diagnostic scanner can be particularly helpful in identifying specific faults that may not be immediately apparent, allowing for a more targeted approach to repairs. Additionally, ensure that the speed sensor is functioning properly, as it plays a critical role in maintaining a consistent speed. It's also advisable to examine related systems, such as brake lights and the speedometer, since issues in these areas can indicate broader electrical problems. While minor issues like blown fuses are frequently the cause of cruise control failures, be aware that more serious concerns, such as a check engine light, may also need to be addressed. By maintaining a vigilant and methodical approach, you can effectively diagnose and resolve cruise control issues, enhancing both your vehicle's performance and your overall driving safety.

What Could Cause the Cruise Control to Malfunction in a Lexus LC500h?

When dealing with cruise control malfunctions in a Lexus LC500h, it's essential to understand the common problems that could be causing the issue. Start by inspecting the control module, sensors, and switches, as failures in these components are often the root of the problem. Additionally, check the throttle actuation system, including the throttle position sensor, since any discrepancies here can directly impact cruise control functionality. Blown fuses should also be examined, as they can interrupt the power supply necessary for the system to operate. Furthermore, the brake pedal position sensor plays a crucial role; if it’s malfunctioning, it can prevent the cruise control from engaging properly. Don't overlook the throttle body, as any malfunctions here can disrupt the entire system. Lastly, consider the PRNDL/shifter position switch and the engine control unit (ECU), as issues in these areas can also lead to cruise control failures. By systematically checking these components, you can effectively diagnose and resolve the cruise control issues in your Lexus LC500h.

Why is the Cruise Control Not Working in a Lexus LC500h?

When the cruise control in your Lexus LC500h is not functioning, it is crucial to address the issue promptly, as neglecting it could lead to safety risks and further complications. Common culprits include a malfunctioning control module, faulty sensors, or issues with the throttle actuation system. For instance, a failed throttle position sensor can cause the engine's computer to mismanage fuel delivery, resulting in black exhaust emissions. Additionally, problems with the engine control unit (ECU) or the cruise control module itself can disrupt the system's operation. Other potential causes include issues with the vacuum actuator, broken cables, or even a blown fuse. Each of these problems not only affects the cruise control's performance but could also indicate underlying issues that may compromise vehicle safety. Therefore, diagnosing the specific cause of the malfunction is essential to implement the right repair strategy and ensure your vehicle operates safely and efficiently.

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