What Does FCW System Failed Mean?

Does your vehicle have a forward-collision warning (FCW) system? In recent years, auto manufacturers have added the driver assist system to an increasing number of their vehicle models as standard issue safety equipment.

FCW has worked quite well since its introduction. According to a study by the Insurance Institute for Highway Safety (IIHS), an FCW system can lower the risk of a rear-end crash by 27 percent. However, the feature isn’t perfect, and you might learn that your vehicle’s FCW system failed. If that happens, you must identify what caused the problem and apply the appropriate corrective measures.

What Does FCW System Failed Mean?

It indicates that the FCW system no longer works. One or more of the system’s components has failed, requiring repairs or replacement.

Most FCW systems have a warning light on the dashboard or another highly-visible location. When something goes wrong with the FCW, the warning light illuminates.

To better understand what a failed FCW system entails, let’s look at the FCW system on the Honda Accord.

What Does FCW System Failed Mean on the Honda Accord?

The Honda Sensing suite is part of the Japanese company’s Advanced Driver Assistance System (ADAS). It features an integrated FCW system that draws information from a sensor network distributed throughout the vehicle.

Depending on the vehicle model and iteration of the FCW, the sensors can include cameras, lasers, radar, or a combination of two or all three types.

If one of the FCW sensors stop working, it can reduce the effectiveness of the forward-collision warning system. In the worst-case scenario, all sensors might fail, rendering the FCW system blind.

Bad Weather

Do you live in a state that experiences severe weather like thick fog, torrential rain, and heavy snowfall? Foul weather can interfere with how the FCW sensors operate. Depending on the scenario, the weather can trick an FCW sensor into either reporting a nonexistent collision hazard or failing to notice a real obstacle.

Heat-Related Internal Damage

The FCW sensors operate within an optimal temperature range. If they get too hot, their internals will overheat, causing components to burn out or melt. Heat-related damage can make an FCW sensor malfunction or fail.

One of the most common reasons for heat damage to FCW sensors in a Honda Accord is the cooling system. Like other vehicles, the Accord’s radiator vents heat through the front grille.

Some of the FCW sensors are on the vehicle’s front end, and heat vented from the radiator can reach the sensors, raising their internal temperatures to excessive levels. Overheated sensors can get seriously damaged.

Other possible reasons behind an FCW system failure in the Honda Accord include the following:

Wear and Tear

All vehicle parts and components eventually get worn down by use and exposure to the elements. The various sensors that serve as the eyes and ears of the FCW system are subject to general wear. As an FCW sensor wears out, it becomes less effective. It might even fail earlier than its expected service life.

Preempt this problem with regular checkups that can identify if one or more FCW sensors have worn out.

Software Issues

The Honda Accord FCW system takes its cues from a computer that runs on software. Sometimes, the software might develop a glitch that causes the FCW to operate erratically until the computer receives a patch that fixes the bug. The FCW’s software might also fall behind the latest version and require an update.

Faulty FCW Sensors

Honda Sensing draws readings from a plethora of sensors. Depending on factors like the vehicle’s model and model year, the FCW system can have cameras, lasers, radar, or a combination of those devices.

The FCW sensors can break down for various reasons. You’ve already read what overheating and general wear can do to a sensor. Other possible issues include corrosion from exposure to moisture and wiring issues like grounding and shorting.

What Is the FCW System?

Also called the forward-collision alert, the FCW system is an advanced driver assistance system found in many recent vehicles. It warns you about the risk of hitting an obstacle, usually another vehicle in front of you.

Manufacturers developed proprietary FCW systems for use on their vehicle models. Honda bundles its FCW system with Honda Sensing while Audi does it with its Pre Sense package. Meanwhile, Mercedes-Benz combined its FCW and Automatic Emergency Braking (AEB) system to create Active Brake Assist.

How Does FCW Work?

The FCW system determines the location of obstacles ahead of your vehicle and how far each object is from your vehicle’s front. It also takes into account the speed at which you’re driving. If the FCW calculates that you might hit an obstacle, it will alert you about the impending collision.

Some vehicles integrate their FCW systems into the automatic emergency braking. These combined systems can automatically slow down or stop the vehicle without driver input, but the typical standalone FCW relies on the driver to hit the brakes in response to the warning of an imminent collision.

FCW System Types

You can sort FCW systems into two types according to their capabilities. The standard forward-collision warning system searches for other vehicles using cameras, lasers, and radar scanners.

However, this type of FCW is only programmed to recognize other vehicles. It cannot identify pedestrians as obstacles, so it won’t warn you if someone decides to cross the road.

The second type is the FCW with pedestrian detection. In addition to searching for vehicles, it recognizes pedestrians and will alert you of their presence. Some of these FCW systems can also identify cyclists and sufficiently large animals.

Additional capabilities might differ between individual FCW systems. Some examples only work within the low speed limits mandated for urban roads, while others can operate at higher speeds. And while many FCW systems only scan the area ahead of the vehicle, others also have sensors mounted on the rear that warn you about incoming rear-end collisions.

When in doubt about the exact capabilities of the FCW system of your vehicle, consult your owner’s manual. Knowing what the FCW can and cannot do will help keep you, your passengers, other drivers, and pedestrians safer.

How to Fix a Failed FCW System

If you get an FCW system failed message, you must bring your car to a certified shop that offers ADAS calibration and repair services.

The mechanics will recalibrate the FCW system during and after the repair process. They will also perform other tasks like updating the software and resetting the repaired system.

Ask the repair shop if they have the necessary equipment and expertise to handle FCW system repair and maintenance. Most shops don’t offer such services because the process requires a large space and prohibitively costly equipment.

To repair FCW systems, you will need to go to a shop that does ADAS repairs and calibrations. All of these systems require an ADAS calibration during and after repairs, as well as software updates, resetting systems, etc.

–Anthony Harlin, ASE Certified Master Automobile Technician