Where are the sensors on a pre collision assist?

The sensors behind a pre-collision assist system are typically located at the front of the vehicle: primarily a forward radar unit and a camera mounted near the windshield. The exact spots vary by make and model, and some vehicles also use additional sensors for short-range detection.

In practice, the radar and camera work together to detect vehicles, pedestrians, and other obstacles, and trigger warnings or automatic braking if needed. The radar is usually embedded in the grille or bumper area, while the camera sits behind the windshield above the rearview mirror. Some vehicles add ultrasonic sensors or other tech for extra coverage, though sensor layouts can differ widely between models and years.

Core sensors powering pre-collision assist

Most systems rely on two primary sensing modalities, with optional extras depending on the vehicle:

• Forward radar sensor (millimeter-wave): measures distance and closing speed to vehicles and obstacles. Location: behind the front grille or in the lower bumper/valance area.


• Forward-facing camera: analyzes objects, pedestrians, cyclists, and sometimes lane markings. Location: mounted behind the windshield at the top center, near the rearview mirror.


• Ultrasonic sensors (optional): provide very short-range detection, often used for parking assist and close-proximity alerts. Location: around the front bumper edges.

These components usually feed a central processor that decides if warnings or automatic braking are warranted. The exact mix and placement vary by model and year, with some vehicles leaning more on cameras or radar than others.

Where you’ll typically find them on most cars

Front-end sensor placement is designed to maximize visibility while protecting the hardware from dirt and damage:

• Radar sensor: commonly tucked behind the front grille or integrated into the lower bumper/valance.


• Camera: typically behind the windshield, near the top center, directly facing forward.


• Additional near-field sensors: often located around the front bumper for close-range detection, primarily tied to parking or cross-traffic aids.

Proper sensor function requires clean, unobstructed surfaces. Dirt, snow, ice, or stickers can degrade performance, and any warning lights on the dash should prompt a check by a technician.

Brand variations and model-specific layouts

Sensor layouts differ by manufacturer and model. Some vehicles integrate multiple sensors into a single front-end module, while others spread components across the bumper and upper fascia.

Typical layout patterns observed in pre-collision systems include the following:

Typical layout patterns

• Radar and camera housed together in a shared front-end unit behind the grille or bumper.


• Radar in the bumper area with a separate camera housing behind the windshield.


• Dual-camera or multi-sensor arrays in some newer designs to broaden field of view and improve redundancy.

These arrangements aim to balance coverage, reliability, and repairability. If you’re unsure about your vehicle’s PCA sensor locations, consult the owner’s manual or contact the dealership for model-specific diagrams.

Maintenance and safety tips for sensor performance

Keeping sensors clear and properly aligned is critical to reliable performance:

• Regularly clean the area around the camera view (typically near the rearview mirror) and ensure the windshield is free of glare and obstructions.


• Keep the front grille and bumper free of dirt, snow, ice, and debris that could cover radar sensors.


• Avoid aftermarket decals, paint protection films, or bumper accessories that could interfere with sensor housing.

If you notice warning lights, abnormal braking behavior, or the system not engaging as expected, have the sensors inspected by a qualified technician. Misalignment or damage may require recalibration or replacement.

Summary

Pre-collision assist sensors are predominantly located at the vehicle’s front: a forward radar unit hidden in the grille or bumper and a camera mounted behind the windshield near the rearview mirror. Some cars also use ultrasonic sensors for close-range detection. While placement can vary by make and model, keeping these sensors clean and unobstructed helps ensure the system can warn you or apply automatic braking when needed. Always refer to the owner’s manual for your specific vehicle’s sensor layout and maintenance guidelines.

Where are ACC sensors located?

The adaptive cruise control sensor is typically located in the front grille or lower bumper and is often a radar unit concealed behind a plastic panel. Some systems also use a forward-facing camera located behind the windshield, usually near the rearview mirror.
 
This video shows the location of the adaptive cruise control radar module: 43sMACTFORDEDGEYouTube · May 3, 2025
Radar sensor

• Location: Usually in the lower part of the front grille or bumper, sometimes hidden behind a black plastic panel. 
• Function: Detects the distance to the vehicle ahead. 
• Maintenance: Keep the area clean of dirt, bugs, snow, or ice, as obstructions can disable the system. 

Camera sensor

• Location: Behind the windshield, typically in the upper area in front of the rearview mirror. 
• Function: Complements the radar sensor by recognizing lanes and other vehicles. 
• Maintenance: Keep the windshield clean and free of smudges or condensation. 

How to clean a radar sensor?

To clean a car's radar sensor, use a soft cloth, like a microfiber cloth, to gently wipe away dirt, snow, ice, or grime. For stubborn spots, you can dampen the cloth with water or a mild car washing detergent. Avoid abrasive materials, strong impacts, or stickers on the sensor's surface to prevent damage. 
This video demonstrates how to clean a radar sensor: 50sVehicle FreakYouTube · Sep 29, 2023
Step-by-step cleaning guide

1. Locate the sensor: The sensor is typically behind the front grille, often integrated into the front emblem or bumper. Check your owner's manual for the exact location. 
2. Wipe with a soft cloth: Use a dry, soft cloth (like microfiber) to gently wipe the sensor's surface. 
3. Use a damp cloth for stubborn dirt: If dirt, bugs, or grime remain, lightly dampen the cloth with water or a mild car washing detergent and wipe again. 
4. Dry the sensor: Use a separate dry, soft cloth to gently dry the sensor completely. 
5. Inspect for damage: After cleaning, check for any physical damage to the sensor or its cover. 

Important considerations

• Avoid abrasive materials: Never use abrasive cloths or materials that could scratch the sensor's surface. 
• Do not use excessive force: Avoid applying strong impact or using excessive force when cleaning. 
• Avoid stickers: Do not place any stickers, including transparent ones, on the radar sensor or its cover. 
• Check your owner's manual: Refer to your vehicle's owner's manual for specific cleaning instructions and sensor locations for your model. 

How to reset pre-collision assist?

To reset a pre-collision system malfunction, first try a simple car restart. If that fails, clean the front sensors and camera lens, as dirt is a common cause. A more thorough reset can be done by disconnecting the negative battery terminal for 10-15 minutes, or by checking and potentially replacing any blown fuses. 
Simple resets

• Restart the vehicle: Turn your car off, wait for 5 to 10 minutes to allow the computers to power down, and then restart it. 
• Clean the sensors: Wipe down the front of the vehicle, paying special attention to the area behind the brand emblem and the front windshield, as dirt or debris can block the camera and radar sensors. 

This video demonstrates how to clean the pre-collision sensors and restart the vehicle: 57sCar FixYouTube · Jul 2, 2025
Advanced resets

• Disconnect the battery: Disconnect the negative battery terminal for about 10 to 15 minutes to fully power down the electronics. Remember to reconnect the terminal securely before starting the car. Some models may require a longer time or connecting the terminals together after disconnection to fully drain the reserve voltage.
• Check fuses: Inspect the vehicle's fuses to see if any related to the pre-collision system have blown. A short circuit could cause a fuse to blow. 

When to see a professional

• If the warning persists after these steps, there may be a more complex issue like a faulty sensor, a wiring problem, or a need for a professional diagnostic tool.
• A dealership or a mechanic with the correct diagnostic software can read the error codes and perform any necessary recalibrations or repairs. 

Where is the pre-collision sensor located?

The pre-collision assist sensor is typically located in one of two places: a radar sensor behind the front bumper/grille and a camera near the rearview mirror on the windshield. The radar sensor is often in the center of the lower grille, behind a fascia cover. The system relies on both sensors, so it's important to keep both the front grille area and the windshield area in front of the camera clean.
 
This video shows how to troubleshoot and clean the sensors: 56sCarnivautoYouTube · Aug 29, 2025

• Radar Sensor: Located behind the front bumper or in the grille, often behind a plastic fascia cover in the center of the lower grille. 
• Camera: Located on the inside of the windshield, near the rearview mirror. 

You can watch this video to see where the sensors are located: 1mNexologyYouTube · Aug 17, 2025