Lexus Pre Collision System Malfunction: (Causes, Fixes + Prevention)

lexus pre collision system malfunction

The Lexus Pre-Collision System (PCS) is an advanced safety feature designed to help drivers avoid or mitigate the damage caused by accidents.

However, like any other sophisticated technology, it is not immune to malfunctions.

In this in-depth article, we will explore the causes of Lexus PCS malfunctions, how to fix them, and preventive measures to ensure that your PCS remains in optimal working condition.

Importance of Pre-Collision System in Lexus Vehicles

The Lexus PCS is an essential safety feature that uses state-of-the-art radar sensors to monitor the surroundings and detect potential threats.

When a collision is imminent, the system sets off a high-pitched buzzer and displays a warning message to alert the driver to take evasive action. In addition, the PCS can automatically apply the brakes to help avoid or reduce the impact of a collision.

By helping to prevent accidents and minimize injuries, the Lexus PCS has become an indispensable safety tool for modern drivers.

However, it is crucial to understand the system’s limitations and ensure that it is always active and functioning optimally.

How the Lexus Pre-Collision System Works

The Lexus PCS uses a set of small radar detector sensors located at the front of the car to monitor the vehicle’s surroundings continuously.

These sensors emit quick bursts of high-frequency radar waves, which bounce off obstacles and return to the sensor.

A separate unit within the sensor calculates the time it took for the radar waves to bounce back, allowing the PCS to determine the distance, speed, and relative velocity of nearby objects almost instantly.

This information enables the PCS to provide audible and visible warnings when there is a potential threat. If necessary, the system can automatically apply the brakes to help avoid or reduce the impact of a collision.

Common Causes of Lexus Pre-Collision System Malfunction

Several factors can cause the Lexus PCS to fail, compromising the effectiveness of this cutting-edge safety technology. Some of the most common causes of PCS malfunctions include:

Dirty Radar Sensors

The radar sensors in your Lexus are located behind the vehicle’s front grille and can become obstructed by dirt, debris, snow, or ice.

When the sensors are dirty, they cannot properly detect obstacles on the road, increasing the risk of an accident. Regular cleaning of the radar sensors is essential to prevent this issue.

Unprotected PCS System

Rodents can cause damage to the PCS by chewing on wires or other components of the system. Most insurance providers do not cover this type of damage, so it is vital to take preventive measures to protect your PCS.

Incorrectly Installed Tow Hitch

When installing a tow hitch, it is crucial to ensure that it does not obstruct the radar sensor. An incorrectly installed tow hitch can cause the PCS to malfunction. Always have a qualified professional install your tow hitch to avoid this problem.

Defective Airbag Sensor

A faulty airbag sensor can cause the PCS to malfunction. The airbag sensor is located at the front of the vehicle and is responsible for detecting accidents and deploying airbags.

If the airbag sensor is defective, it can interfere with the proper functioning of the PCS.

Varying Tire Conditions

Tires that are very worn or improperly inflated can cause the PCS to malfunction. Additionally, using tires of different sizes than specified or installing tire chains can also lead to PCS issues.

Ensuring that your tires are in good condition and correctly inflated is crucial to the proper functioning of your Lexus PCS.

Other Factors

Other factors that can cause PCS malfunctions include strong sunlight or lighting conditions that interfere with the sensors, driving off-road, or when the car is raised, and the tires are rotating freely. In such cases, it may be necessary to disable the PCS temporarily.

Read also >> Pre Collision System Malfunction: How To Fix? (Step by Step)

Read also >> Auxiliary Battery Malfunction: How To Fix? (Step by Step)

Read also >> Can You Leave a Battery Charger Connected? (Is It Safe?)

Fixing Lexus Pre-Collision System Malfunctions

When your Lexus PCS malfunctions, it is crucial to address the issue as soon as possible. Depending on the severity of the problem, you may need to take different steps to get the system back to its optimal working condition.

Minor Malfunctions

For minor PCS malfunctions, you can try resetting the system by disconnecting the battery for a short period and then reconnecting it. This process can often clear up minor glitches causing the system to malfunction.

Severe Malfunctions

If your Lexus PCS is experiencing more severe issues, it is best to have the system inspected and repaired by a qualified professional.

Electrical problems often cause severe malfunctions, and a technician with proper training and experience should handle them.

Resetting Your Lexus Pre-Collision System When Malfunctioning

If you notice that your Lexus PCS is malfunctioning, you can take the following steps to reset the system and restore its functionality:

  1. Inspect the fuse box and ensure that the PCS fuse is not blown. If you find it blown, replace it with a new one.
  2. Disconnect the battery and then reconnect it. This action resets all electronic systems in your car, including the PCS.
  3. If the problem persists, visit a professional technician for inspection and repair.

Signs That You Need to Reset Your Lexus Pre-Collision System

Be vigilant while driving your Lexus and watch out for any of the following signs that may indicate the need to reset your PCS:

  • The system is not working correctly.
  • The car ahead moves out of range of the PCS sensors.
  • There is a problem with the PCS laser sensor.
  • The system has been turned off.

Upon noticing any of these warning signs, it is crucial to reset your Lexus PCS to ensure its proper functioning.

Reducing the Risk of Pre-Collision System Malfunction

To minimize the chances of your Lexus PCS malfunctioning, consider the following tips:

  • Keep the software updated and maintain the system regularly.
  • Do not rely too heavily on the PCS and be aware of its limitations.
  • Remember that the PCS is a tool, not a replacement for safe driving practices.

Disadvantages of the Lexus Pre-Collision System

While the Lexus PCS is a top-of-the-line safety feature, it has its drawbacks:

  1. The driver is ultimately responsible for driving safely, and relying too much on the PCS can be dangerous. The system does not prevent collisions; it only reduces the risk of an accident.
  2. The effectiveness of the PCS can change over time due to varying conditions. As a result, it is essential to use the system only when necessary and avoid inspecting it as it may cause a failure and lead to an accident.

Despite these disadvantages, maintaining your Lexus PCS is crucial for ensuring your safety on the road.

If you cannot determine the cause of your PCS malfunction, consult your dealership or a certified auto repair expert for professional diagnosis and assistance.

Can you drive with pre-collision system malfunction?

It is not recommended to drive with a malfunctioning Pre-Collision System (PCS) in your Toyota car, as it can lead to false alarms and other safety issues.

The PCS is designed to detect potential collisions and alert the driver to take corrective action. If the driver fails to respond, the system applies the brakes to avoid or mitigate the impact.

Malfunctioning PCS is a common problem that can stem from several causes, such as dirty sensors, malfunctioning components, electrical problems, software glitches, tinted or dirty windshields, and environmental factors such as heavy rain or fog.

Can you turn off collision warning?

Yes, the pre-collision system (PCS) in Toyota vehicles can be turned off or adjusted for sensitivity using the MID or gauge cluster controls. However, disabling the PCS is not recommended as it can lead to safety issues and fail to prevent a crash.

The PCS uses a radar sensor to alert drivers and automatically apply the brakes if it detects the vehicle is about to hit an object.

Similarly, the Ford Pre-Collision Assist system can have its Active Braking feature turned off through the Settings menu, but the overall system cannot be completely disabled.

It is important to note that malfunctioning PCS systems should be resolved by a certified Toyota dealership to avoid false alarms and other safety issues.

Does Lexus have automatic braking?

Yes, Lexus has automatic emergency braking technology, which will be standard on nearly all Toyota and Lexus vehicles by the end of 2022.

However, if the pre-collision system (PCS) malfunctions, it is not recommended to drive the vehicle until the issue is resolved by a certified Toyota dealership to ensure the safety of the driver and passengers.

While the PCS can be turned off or adjusted for sensitivity, disabling it is not recommended as it can lead to safety issues and fail to prevent a crash.

As for Ford Pre-Collision Assist system, its Active Braking feature can be turned off but the overall system cannot be completely disabled.

Lexus PRE-Collision system malfunction [ Solved ] >> Check out the video below:


The Lexus Pre-Collision System is an advanced safety feature designed to help drivers avoid or reduce the impact of accidents.

However, malfunctions can occur, making it essential for drivers to understand the common causes of PCS issues and how to fix them.

Regular maintenance, being aware of the system’s limitations, and consulting a professional technician when necessary are all crucial to ensuring that your Lexus PCS remains in optimal working condition, protecting you and your passengers on the road.

Steve P.

Steve is an automotive technician, technical writer, and Managing Editor. He has held a lifelong passion for cars, with a particular interest in cars like the Buick Riviera. Steve is based in Boise, Idaho.

Recent Posts

error: Content is protected !!