ACC FCW Limited Functionality: Here’s How to Solve it

One fine morning, you started your Jeep and suddenly saw a message popping out on the screen. It says, “ACC FCW Limited Functionality, Service Required”. You get confused. Does this mean something’s wrong with your Jeep?

How to remove this ACC FCW Limited Functionality from your screen?

To remove ACC FCW Limited Functionality from your screen, you have to reset the ACC/FCW first. Then, you have to clean the windshield, front camera, and ACC/FCW sensors. Keep them in the correct alignment and check the connection. Recalibrating the camera also helps in this case.

This is a small glimpse of what works in removing the message from your car’s screen. For more details, keep reading the article till the end.

How Concerning is the ACC/FCW Limited Functionality?

The ACC/FCW limited functionality problem isn’t a severe problem for expert drivers. But drivers who rely on this feature for safety purposes entirely should be concerned about the matter. 

Just like a bad mass air flow sensor increases transmission problems, the limited functionality of ACC/FCW sensors can increase the risk of unwanted accidents. 

It’s because the ACC or FCW both work to warn the driver about any obstruction on the front end of the road. These two technologies signal the driver using sensors by scanning the road. But due to some limitations, the technology can cease to work.

According to the Pacifica user manual, you can drive with ACC/FCW limited functionality warning popping up on your screen. But in this case, you have to be aware as active braking won’t be entirely available. 

Why is the Screen Showing ACC/FCW Limited Functionality?

Having “ACC/ FCW limited functionality” appearing on your screen doesn’t always mean you have a problem in your vehicle. It can be an electrical malfunction that causes a false display of the message. 

However, if it’s not an electrical glitch, the following 6 reasons are responsible for your screen showing ACC/FCW limited functionality. 

Reason 1: Mispositioned Sensor Behind Windshield Mirror

One of the major reasons you’ll see the message pop out on your screen is the wrongly positioned sensor behind the windshield mirror. This often happens when you get a new windshield replacement. 

Reason 2: Adverse Weather Conditions

When the temperature is extremely low, snow or ice can cover up the sensors behind the windshield. It can also happen when the sensors are dirty. Dust and debris block the sensor’s radius. So, the ACC or FCW can’t function properly. 

Reason 3: Faulty Wiring System in the Lower Grill

Again, if the sensor’s wiring in the lower grill area is defective, you’ll see the warning message. The wire can be prone to a short circuit. In fact, damaged sensors can also cause to send you warning signals.   

Reason 4: Defective Camera Settings

Sometimes you’ll see a message popped up on your screen – ‘acc/fcw limited functionality front camera service required’. This means the camera is unable to track any vehicle or object. In this case, you have to fix the problems related to the camera. It is also a kind of ACC/FCW limited functionality. 

Now, you should remember one thing here. The limited functionality issue is different than the “ACC/FCW unavailable service” message on the screen. You’ll have to apply for a different kind of fix for it. 

How to Fix ACC/FCW Limited Functionality?

To fix the ACC/FCW limited functionality, you must check the 4 causes first to check where the problem is. Depending on the cause of the problem, you should apply any one or two of the following fixes.

Reset the ACC/FCW

As I’ve mentioned earlier, the message can pop up due to electrical malfunction, you need to reset the ACC or FCW system first.

To do this, you should follow the steps below:

1. First, remove the battery from the vehicle. You should pull out the negative terminal first and then, take out the positive terminal.
2. After that, wait for at least 15-20 minutes. This will help to deplete the power entirely from the vehicle.
3. Then, connect the battery again by correctly adjusting the terminals.
4. Finally, check the dashboard and you should see the message disappear.

But if it’s not an electrical malfunction, you should follow the next segments. 

Clean the ACC/FCW Sensors, Front Windshield and Camera

The most common reason for ACC/FCW limited functionality is dirty sensors or windshield. So, if you’re still seeing the message after resetting the car, you have to check for dirt or snow on the ACC or FCW sensors. If they are dirty, you should immediately clean them to clear all the obstructions.

You can either use only wet glass wipes or windshield washer fluids to clean a FCW sensor or ACC sensor. Make sure you’re cleaning the surface of the sensors, camera, and windshield. You don’t need to dismantle the sensors, windshield, or front camera for cleaning.  

Warning: In this case, you should avoid Windex or any cleaning compound containing Ammonia. Or else, you’ll risk the sensors getting corroded.  

Calibrate Front Camera Settings

If the windshield, sensors, and camera are clean, you should inspect the forward camera closely. Sometimes, the vehicle shows ACC/FCW limited functionality because the front camera requires servicing. 

So, if you notice this kind of message, you have to calibrate the front camera. But if the camera isn’t calibrating, you should check if there’s a wiring connection issue. Fix the wiring to the correct position and try calibrating it again.

If it doesn’t work, you should check the dashboard, and often it leads to replacing the front fascia. 

What if Any of The Fixes Don’t Work?

Now, this is a rare case but you might see not a single fix mentioned above is working for you. In this case, you should contact the dealer immediately and send your vehicle for a thorough inspection.

If they still fail to provide you with the solution, it’s better to change your vehicle. You can also file for a breach of contract for diminished resale value. Note that it’ll fall under the Lemon Law.   

ACC/FCW Limited Functionality Service Required for Different Brands

Now, vehicles from different brands show the ACC/FCW limited functionality for the same reasons I’ve explained earlier. Here’s a snapshot of the most frequent problems in each type of vehicle for ACC/FCW limited functionality.

Vehicle Brands	Reasons for ACC/FCW limited functionality
Jeep Cherokee	Camera alignment
Maserati	Dirty sensors
Alfa Romeo Stelvio	Muddy WindscreenMisaligned cameraNon-functional interface between Haptical Lane Feedback Module and the Driver’s Assistant Module.
Chrysler Pacifica	Internal malfunction
Dodge Durango	Wrongly windshield sensor placementDirty windshield

ACC/FCW Limited Functionality Jeep

You’ll face the ACC/FCW limited functionality jeep Cherokee mostly because of camera alignment issues. 

If you keep the camera lift on, you’ll be seeing the acc/fcw limited functionality service required message in the Jeep Cherokee. Especially, it’s more evident in the 2021 Jeep Cherokee car. 

So, what you have to do is change the alignment of the camera. Maintain the correct angle or height and recalibrate it. The problem will be solved immediately. 

ACC/FCW Limited Functionality Maserati

In Maserati, the ACC/FCW limited functionality occurs mostly for dirty sensors and cameras. You’ll also get a windshield cleaning warning. This happens when mud or snow blocks the sensors. They take a hit on the performance.

So, if you notice a problem like that in Maserati, you have to clean all the sensors immediately. Also, make sure you wipe out any dirt from the windshield and the front camera.  

ACC/FCW Limited Functionality Alfa Romeo Stelvio

In the Alfa Romeo Stelvio, this message pops up mostly because of the dirty windscreen and misaligned front camera. 

So, if your Alfa Romeo Stelvio is showing the same message, you should first, clean the windscreen thoroughly. Then, check if the front camera is aligned properly. 

You should also check whether the interface between the Driver Assistant and Haptic Lane Feedback is functioning. If they’re not, fix the connection issues and you won’t get that message again. 

ACC/FCW Limited Functionality Chrysler Pacifica

When there’s an internal malfunction, the Chrysler Pacifica shows the ACC/FCW limited functionality. In this case, it’s better to contact the professionals and give an internal checkup on your car.

However, you can drive in this condition but the active braking won’t fully work.  

ACC/FCW Limited Functionality Dodge Durango

You’ll get the ACC/FCW limited functionality message in Dodge Durango for improper windshield sensor placement. You need to check the position and correctly align both the windshield and the sensor.

Well, sometimes it happens when the windshield is faulty. In this case, you should install a new windshield in the correct position. Make sure you take off the plastic cover before placing it on the car. And don’t forget to keep the windshield clean and clear all the time. 

Frequently Asked Questions (FAQs):

What does it mean when the ACC light comes on?

When the ACC light comes on it means the ACC is unavailable and it requires action. It’s a signal that says you should inspect the internal components to figure out the problem. As soon as you see the light, you should stop the car and turn off the engine.  

Why does the FCW light come on?

The FCW light comes on to show that there’s an obstruction ahead in front of your vehicle. The FCW scan all the possible collisions and signal you about them through sensors. 

Does ACC drain your car battery?

No, ACC doesn’t drain your car battery. It’s because the ACC doesn’t use a car battery to function. The car battery only drains out when there are multiple electrical components connected but the battery isn’t charged.  

Does ACC use more fuel?

No, ACC doesn’t use more fuel. In fact, it saves fuel by adapting the speed according to the sensors. As the travel speed, time, and mileage reduces, the ACC saves fuel consumption.

Final Words

Hopefully, this article helped you to be clear about the ACC FCW limited functionality entirely. You should try every fixing method I’ve described above until the message completely disappears. But if it doesn’t fix the car, you should let the professionals take a look at it.