ACC FCW Unavailable Service Required: 15 Tips to Fix the Warning

As you speed down the road, suddenly, the word “BRAKE!” flashes on the instrument panel, and the message “acc fcw unavailable service required” appears on your screen. This is scary. Should you be worried? Well, calm down and keep driving. It occurs when there are loose connections within the ACC/FCW system, dirty or malfunctioning sensors within the circuit (such as the radar sensor or its alignment), a dirty lower bumper, an inappropriate grille, or excessive light reflection, among other things.

Continue reading to learn why the “acc fcw unavailable service required” warning appears in detail and how you can try to resolve it on your own.

What Does the “ACC FCW Unavailable Service Required” Warning Mean?

ACC stands for Adaptive Cruise Control. When using ACC, your speed is adjusted based on the traffic flow in front of you. It does this by using the Adaptive Cruise sensor. It is the object with a black eyeball-like appearance in your car’s lower grille. Make sure that it is in good shape and is clean.

If the system shuts down and “ACC/FCW Unavailable Service Required” or “Cruise/FCW Unavailable Service Required” appears on the instrument cluster, an internal system error or a temporary malfunction may limit ACC functionality. The car can still be driven, but ACC won’t work immediately. If this happens, try turning on the ACC again after an ignition cycle.

The FCW, or Forward Collision Warning system, scans the road ahead of you to look for obstructions. It can recognize other cars, people walking, stationary objects, etc. Your vehicle’s FCW service will measure the space between you and the object in front of you as you drive. It accomplishes this by utilizing the tiny round sensor that detects vehicles in front of you at the bottom of the front bumper.

When Does the FCW Light Turn On?

The Forward Collision Warning or FCW warning light turns on when it detects a potential collision while scanning the road before you. It works with your automatic emergency braking system, and your car will stop or slow down when the obstacle is detected. So, as soon as the sensor picks up any potential obstacle, it will alert you with various warnings, such as sound or light.

The instrument cluster will display an “acc fcw unavailable service required” warning or Service 4WD System when there is a malfunction or temporary fault in the FCW system. You might experience additional problems like clicking and thumping noise when accelerating from a stop or in reverse.

Every modern car has these features. These are crucial safety features for your vehicle. According to statistics, these systems reduce the likelihood of accidents. You can still drive your car even though these features are disabled, but you shouldn’t.

Reasons Behind the “ACC FCW Unavailable Service Required” Warning & Possible Solutions:

Don’t panic if you see the warning “acc fcw unavailable service required.” There are many potential causes for its appearance. But the majority of them are simple to fix. Test them out first. You can then go to your dealership.

The following is a list of both typical causes for the “acc fcw unavailable service required” warning:

1. Dirty Front Sensor

The most typical problem is this one. If you travel on dirt or poorly constructed roads, driving causes you to kick up mud and dust. Your Jeep’s lower bumper is clogged with debris, dust, and mud from the road, which makes the sensor ineffective. The sensor cannot function properly because it misinterprets dirt containing foreign objects. Consequently, you will see the warning “acc fcw unavailable service required.”

Fortunately, resolving this problem is simple. The ACC and FCW should turn back on with a simple sensor cleaning. Make it a habit. You’ll need a microfiber cloth, warm water, and car shampoo.

2. Driving in Bad Weather

Another frequent cause of “acc fcw unavailable service required” warnings is terrible weather. One example of bad weather is heavy snowfall. The snow and ice lumps significantly reduce your sensor’s visibility range. As a result, ACC and FCW will both shut down, causing the message to display. Light showers typically don’t result in this problem, but heavy rains might. Hailstorms work similarly. In this case, your Jeep is operating perfectly. Unfortunately, the circumstances will persist as long as it is terrible outside.

There is no proper solution as there is no systemic malfunction, and the situation improves with the weather. The sensor’s visibility range does, however, decrease during periods of heavy snowfall. So you can take a break and clear the snow lumps as much as possible. The sensor’s visibility range is also limited by periods of heavy rain. Take a break until the rain’s intensity has somewhat decreased. Jeeps experience the same problem during hailstorms. To avoid receiving such warnings, take a break until things improve.

3. Broken Sensor

Because of its fragility, there’s a chance that you damaged the sensor while driving. Any accident or overheating could be to blame. The supporting bracket or your wheel speed sensor might need to be changed. As a last resort, you can carefully inspect it to see if it’s broken. If so, you must replace it, necessitating a dealership trip.

You need to replace the damaged sensor for a smooth ride in your Jeep. However, you can attempt to reset your sensor before replacing it.

To reset your sensor –

Turn the Jeep’s ignition key to the “on” position to initialize it without starting it.
When the light flashes thrice, keep holding the TPMS button.
Start the car, then wait 20 minutes for the sensor to reset.

4. Sensors are Confused by a lot of Light Reflected from Surfaces

The ACC and FCW systems can suffer from a lack of brightness, but too much light can also make them unreliable. The sensor will become “confused” in bright areas, shutting down both systems. Your Jeep will then display the message “ACC/FCW Unavailable, Service Required.” as a result.

Even on sunny winter days, white ground surfaces like snow and ice reflect much light. Some tunnels are lined with reflective tiles, which can cause this issue. If so, the only way to avoid this problem is to avoid these places. Driving around those areas is your only option in such a scenario. Have the attitude that you will receive a warning because that is not always possible while driving. Your car has no system malfunction, so the concern is unnecessary.

5. Installed an Unsuitable Grille

Accidents happen, and the grille is one of the most frequently repaired auto parts. Installing aftermarket grilles isn’t always a good idea, although they might be cheaper than the originals. They may block the ACC and FCW sensors even if they fit your Jeep.

Due to its high photosensitivity, the sensor requires a specific brightness level to operate correctly. The incorrect grille installation could affect the amount of light that reaches the sensor, causing a malfunction and an “acc/fcw unavailable service required” message.

To Fix the Jeep’s Issue with the Incompatible Grille:

Try to repair the original grille rather than replace it. Make sure to replace the grille as closely as possible to the original if necessary. Make sure the Jeep grille is receiving the required amount of light. While replacing the Jeep grille, be careful with every step.

6. Computer Malfunction

It’s also crucial to remember that both systems are controlled by your car’s computer. The message “ACC/FCW Unavailable, Service Required” may occasionally appear even when both components work correctly due to a system error. By momentarily cutting off the power source, you can resolve this. If this fix doesn’t work, visit an auto repair shop with your vehicle if this fix doesn’t work. If everything is OK, a fault code may be stored to give a direction for diagnosis.

7. Loose Connection

The connector for the ACC/FCW module that is located behind the grille may be corroded. You should check this connector and weatherproof it (with dielectric grease). Because a damaged harness connector could allow moisture to enter the connection, it may short out due to corrosion.

Retighten the sensor if it appears to be loose. It might be a pinched ground wire or loose connections in the ACC/FCW system’s loom.

The connector may have condensation inside. It is possible to fry the sensor module, which houses the system’s processing unit. If it is not too late, you should get this checked out and the connector cleaned and sealed while it is still repairable.

8. Electrical Issue

Voltage changes in the can-bus system between the ACC button on the steering wheel and the clock spring are possible. You must spray the cleaning solution on the front of the wheel switch.

All other components could become damaged by incorrect signals sent by the ABS module. Typically, the PCM issues orders to each of the other modules to perform particular tasks. When the ABS gets involved, it obstructs the PCM’s commands.

9. Connectivity Issues

When using the 4G adapter for Uconnect services, ACC (adaptive cruise control)/FCW (forward collision warning) errors may be persistent. In addition to the ACC not functioning, your FCW is inoperable and would not automatically stop the car in an emergency. The error message will persist, and things will eventually get worse. The warning will go away if the 4G adapter is removed.

10. Transmission-related Issues

If your transmission fluid level is low, the error message “acc fcw unavailable service required” may appear. Just fill up the transmission fluid, and you are good to go.

Thoroughly inspect the wire at TCM. Follow the steps for each diagnostic code, and check the event data to see the circumstances under which the code was set. If it is faulty, replace the TCM.

11. PCM Problems

Communication between the FFCM and ACC modules and the PCM can occasionally break down. Examine the PCM and the wiring that leads to the star connector. The PCM may need to be changed if the issue continues.

12. Misaligned Sensor

You can find the front radar sensor misaligned. The ground may appear to it as an obstacle, so it may keep turning itself off to maintain its sanity. It may be out of alignment because the bumper bracket is bent, and someone likely backed into the van to cause this. If there is no snow, rain, mud, or other obstruction and you frequently receive the message “ACC/FCW Unavailable Wipe Front Radar Sensor” or “ACC fcw unavailable service required,” have the radar sensor realigned at a licensed dealer.

13. Battery-related Issues

There might be a problem with the primary battery that requires replacement. If it is a battery issue, fix it, and it won’t happen again.

14. Windshield Issue

The “acc fcw unavailable service required” error may appear because the sensor behind the mirror was improperly installed during a windshield replacement. Although removing the plastic cover makes a difference, you must install a new windshield. Make sure the mirror behind the windshield is clean. No snow, no ice etc.

Ensure the upper portion of the windshield window is clean because the FCW camera is behind it in the rearview mirror. This problem arises because the window is dirty. Additionally, if the windshield has ever had an aftermarket window installed in its place, it may need the sight window necessary for the camera to see. To check while you wait for the codes, start with those items.

According to the owner’s manual, the front radar sensor and windshield must be clear and unobstructed.

15. DTCM Issues

Before beginning to replace parts, check the connections. If there are multiple codes, but no apparent mechanical problems (the car drives perfectly after a restart), the transfer case control module or DTCM most likely has issues.

Replace the transfer control module. If the transfer case is to blame, try replacing it to see if the problem persists. Afterward, swap out the drive train control module. Those who do not have a warranty should begin by checking the DTCM to determine if that is the root of all the issues. It would allow you to save a few thousand dollars.

You should first rule out some of the most common causes of this problem before drawing any conclusions. The most likely reason for the message “ACC/FCW Unavailable, Service Required” is bad weather and poor visibility.

ACC FCW unavailable service required Jeep — Jeep Wrangler JK Unlimited

Tips for Cleaning the Sensors:

The steps for cleaning sensors are as follows-

Add the required amount of car shampoo to a bowl of warm water.
Check the cloth to see if there is any debris; if there is, carefully remove it.
Gently remove any debris from the parking sensor using the microfiber cloth. Use the tip of your finger to apply it in a circular motion for efficient dirt removal.

Reset the System

The ACC and FCW are part of the electrical system in your Jeep. Sometimes a computer glitch will cause a false issue on the dashboard. If so, you can perform a quick reset to fix the problem. This quick fix works most of the time and may save you the trouble of visiting your dealership.

Just take out your battery, that’s all. Ensure that you begin with the negative terminal. Wait 15 to 20 minutes after removal. Your Jeep’s power will gradually diminish during this period until it runs out entirely. Your electrical system resets once it has completely run out of power. After that, you can reconnect the battery to your car and look at the dashboard. The message should vanish if everything is done correctly.

If the problem continues, additional computer problems with your Jeep may occur. You will have to see a mechanic in this situation.

Precautions When Using ACC While Driving

ACC may experience detection problems while driving in some circumstances. In such circumstances, ACC may brake abruptly or late. The driver needs to be on guard and may even need to intervene.

Tips for Jeep Maintenance:

To prevent further problems, here are some Jeep maintenance tips for you:

You must change the oil in your Jeep regularly while keeping a specific time limit for each change.
Check your car’s fluid level and replace it as necessary.
Always keep the sensor clean. Clean the sensor lens gently with a soft cloth. Take care not to scratch the sensor lens.
Don’t remove any of the sensor’s screws. This might result in an ACC system failure or malfunction and call for a sensor realignment.
Consult a licensed dealer for service if a collision has damaged the vehicle’s sensor or front end.
Avoid installing or attaching accessories, such as transparent material or aftermarket grilles, close to the sensor. A failure or malfunction of the ACC system might result from doing so.

Final Words

The adaptive cruise control and forward collision warning safety features are helpful. Although you don’t need them to operate your Jeep, they can save your life occasionally.

The message “ACC/FCW unavailable service required” will appear on your dashboard if a sensor is blocked. The sensor can become blocked by snowfall, rain, or hail, which will cause problems for the ACC and FCW systems. By routinely cleaning the sensor, you can prevent this.

The sensor is very brittle and breaks easily, mainly if you’ve recently been in an accident. You should inspect it after cleaning it. You might need to see a mechanic if it is damaged.

A computer glitch might also be to blame for this problem. Fortunately, you can resolve this by performing a quick reset. This requires briefly removing the battery. Once you plug it back in, the issue should be resolved.

I hope this article has helped you understand the “ACC/FCW Unavailable Service Required Jeep” warning and how to resolve it. Follow the steps mentioned above to address the issues appropriately.

If it still needs to make more difference, get your car checked out by professionals for a better inspection and repair.