Why is my forward collision warning light on?
The forward collision warning light typically means the system has detected a potential collision or there is a fault in the FCW sensors. In most cases it's caused by something obscuring or misaligning the sensors (such as dirt or frost on the windshield, or a damaged bumper), or a sensor/software fault that needs service.
What forward collision warning is and how it works
Forward collision warning (FCW) is a driver‑assistance feature that monitors the distance to vehicles ahead using radar, cameras, or both. When the system senses you're closing too fast, it alerts you with a visual indicator on the dashboard and an audible warning. Some systems also engage automatic emergency braking (AEB) to reduce speed or stop if a collision is imminent. The FCW light can indicate the feature is active or, if it's accompanied by a fault message, that the system needs service. Weather, road conditions, and sensor cleanliness all influence FCW performance and may cause temporary warnings.
FCW vs AEB
FCW is a warning system. AEB uses the same sensors to actually apply braking in a crash‑risk scenario. Depending on the vehicle, you may see the FCW light without AEB operating if the driver hasn't engaged the feature, or if the system is degraded due to a fault.
Common reasons the FCW light is on
Sensor health and visibility are the primary reasons the light may illuminate. Here are the most frequent causes you can check yourself.
- Sensor obstruction: Dirt, mud, ice, or frost on the windshield near the rearview mirror or on the front bumper sensors can block the FCW sensors.
- Sensor misalignment or damage: A collision, bumper replacement, or windshield work can misalign sensors or require recalibration.
- Sensor or system fault: An electronic fault in the FCW camera, radar, or control module can trigger a fault indicator.
- Extreme weather or road conditions: Heavy rain, snow, fog, or glare can reduce sensor performance and trigger a warning or temporary fault.
- Software or calibration issues: A recent software update or calibration procedure can temporarily affect FCW operation.
If the light persists after addressing obvious obstructions or after a software update, schedule a diagnostic with your dealer or a qualified mechanic to prevent loss of a critical safety feature.
What you can do right now
Before seeking service, you can perform simple checks to determine if the light is due to a solvable issue. Always ensure you are safely stopped before inspecting components.
- Inspect and clean the sensors and camera lenses: wipe the windshield area around the rearview mirror and wipe the bumper sensors if visible. Use a soft cloth and avoid abrasive cleaners.
- Remove ice, snow, or dirt from the windshield, camera lens, and front bumper area that could obscure sensors.
- Look for visible damage to the bumper, grille area, or windshield that could affect sensor alignment. If you recently had an collision or windscreen replacement, sensor recalibration may be required.
- Check for other driver‑assist warnings or messages on the dashboard or infotainment screen. Some cars show a specific FCW fault message that instructs service.
- Consider whether a recent software update or recall might be related; check the manufacturer’s site or your VIN for recalls or required updates.
If any of these steps do not clear the light, or if the lights stay on while driving, arrange a diagnostic with a dealership or certified mechanic. Do not rely solely on FCW in this situation.
When to seek professional service
Persistent or multiple fault indicators mean the FCW system may not be reliable, which is a safety concern. Seek service promptly, especially if the light appears after an impact or if you notice reduced performance of other driver‑assist features.
- Persistent FCW or “FCW fault” message remains after performing basic checks.
- Light appears after a collision, windshield replacement, bumper work, or any repair involving front sensors.
- A recall or software update is advised for the FCW system. Check with the dealer using your VIN.
- You experience inconsistent warnings or the system disengages unexpectedly during normal driving.
Keep in mind that FCW is a safety feature, but it may not always operate perfectly. If in doubt, treat the situation with caution and have the system inspected.
Summary
The FCW light serves as both a warning and a diagnostic signal. If illuminated, the most common culprits are sensor obstruction (dirt, ice, snow), sensor misalignment or damage, or a fault in the FCW system. Start with simple at‑home checks—clean lenses and windshields, inspect for damage, and review any recent software updates or recalls—and then consult a professional if the light persists. Always maintain a safe following distance and be prepared to brake manually if needed, even when FCW is functioning.
How to fix forward collision warning light on?
To fix a forward collision warning light that is on, first check for obstructions like dirt or debris on the sensors, grille, and camera lens, then restart the vehicle. If the light remains on, try disconnecting the battery for a few minutes to perform a hard reset, or check your vehicle's settings to ensure the system is turned on and set to a lower sensitivity. If these steps don't work, the system may need recalibration by a professional, as there could be a sensor issue or a need for a software update.
This video demonstrates how to reset the forward collision warning light on some vehicles: 1mCar FixYouTube · Jul 2, 2025
Initial checks and resets
- Clean sensors: Clean the front radar sensor (often behind the grille or logo) and the camera on the windshield. Dirt, bugs, or ice can trigger the warning light.
- Check the windshield: Ensure the windshield is clean and free of damage, stickers, or smudges that could interfere with the camera's view.
- Restart the vehicle: Turn the car off completely, wait about 30 seconds, and then restart it. This can reset minor glitches in the system.
- Disconnect the battery: As an alternative to the simple restart, disconnect the negative battery terminal for a few minutes to perform a hard reset. Reconnect it and restart the car.
Adjust settings and check for other issues
You can watch this video to learn how to adjust the forward collision warning settings on some vehicles: 55sipartout studioYouTube · Aug 5, 2025
- Check system settings: Go to your vehicle's dashboard settings to ensure the forward collision warning system is turned on.
- Adjust sensitivity: If the warning is too frequent, you can often adjust the sensitivity in the system's settings. Try setting it to a lower sensitivity to see if that resolves the issue.
- Inspect the battery: A weak battery can sometimes cause electronic systems to malfunction. Make sure your battery is fully charged and the connections are secure.
When to seek professional help
This video explains how to fix the forward collision warning light if it remains on after performing the initial reset steps: 1mDashboard warning lights YouTube · Dec 25, 2024
- Sensor recalibration: If the light comes on after a minor impact, a collision, or a windshield replacement, the sensors may need to be recalibrated by a professional.
- Software update: Your vehicle may require a software update to fix a bug or glitch that is causing the warning light to stay on.
- Consult a dealer or mechanic: If the problem persists, have a qualified technician diagnose the issue. They can use a diagnostic scanner to read any trouble codes and determine if there's a more serious problem, such as a damaged sensor or faulty module.
Why did my pre-collision light come on?
Your pre-collision light is on due to a potential system malfunction caused by factors like a blocked sensor, bad weather, or a system glitch. You should first check and clean the front-facing sensors and camera, ensure the gas cap is tightened properly, and try a simple system reset by turning the vehicle off and on again. If the light persists, the issue may require professional diagnosis to check for problems with wiring, sensors, or other components.
Common reasons the light comes on
- Blocked sensors: Dirt, snow, ice, or even a bug can block the radar sensor or camera, causing a false alert.
- Inclement weather: Heavy rain, snow, or fog can obstruct the sensors' view and trigger the system to shut down or malfunction.
- System glitches: A temporary electronic glitch can sometimes cause the light to turn on.
- Driver behavior: Frequent, last-minute braking can cause the system to activate more often, though this is usually a warning that the system is working, not a malfunction.
- Other issues: Problems with the battery, after-market electrical modifications, or a faulty gas cap can also trigger the light.
This video explains how to fix and reset the forward collision warning light: 1mDashboard warning lights YouTube · Dec 25, 2024
What to do
- Clean the sensors and camera: Use a soft cloth with a cleaning solution to wipe the front of the vehicle, especially around the grille emblem where the radar sensor is located, and the area of the windshield where the camera is.
- Check the gas cap: Make sure it is screwed on tightly. Some systems can be triggered by a loose gas cap.
- Try a system reset: Park the vehicle, turn it off, wait for at least 5-10 minutes to allow the onboard computers to fully reset, and then start the car again.
- Check for after-market modifications: If you have any aftermarket lights or other electrical accessories, they could be interfering with the system. Check the wiring and connections.
- Adjust sensitivity (if applicable): Some systems allow you to adjust the sensitivity through the vehicle's menu.
- Visit a dealer for diagnosis: If the light is still on after trying these steps, the system likely needs a professional diagnosis to check for a more serious issue, such as a faulty sensor, misaligned camera, or wiring problem.
This video demonstrates how to reset the pre-collision system by disconnecting the battery: 59sHow To DIY Moore YouTube · Aug 9, 2024
Why is my forward collision warning light on my Chevy?
Cause: This message or amber ICON will display if the Forward Automatic Braking (FAB) or Front Pedestrian Braking (FPB) when equipped, has been set to the ``Alert'' setting. This setting disables most FAB or FPB functions.
Where is the forward collision warning sensor located?
The forward collision warning sensor is typically a radar sensor located behind the front bumper or grille and a camera located near the rearview mirror on the inside of the windshield. Both sensors work together to monitor the road ahead and can be obstructed by dirt, bugs, snow, or other debris, which can cause the system to malfunction.
This video shows how to find and clean the forward collision warning sensors: 1mCar FixYouTube · Jul 2, 2025
Sensor locations
- Radar sensor: Located behind the front bumper, often in the lower section of the grille, and behind a plastic cover or fascia.
- Camera: Mounted inside the vehicle on the windshield, usually near the rearview mirror.
Common issues and solutions
- Obstructions: Dirt, bugs, ice, snow, or even a car wash wax can block the radar sensor, and smudges on the windshield can confuse the camera.
- Fix: Clean both the radar sensor area on the front bumper and the camera lens on the inside of the windshield to ensure the system functions correctly.
- Check your owner's manual: For the most accurate information on your specific vehicle, refer to your owner's manual, as the exact location can vary.
