Solutions to potential problems with Blind Spot Assist on the Mercedes-Benz CLA

By Product Expert | Posted in Mercedes-Benz CLA, Tips & Tricks on Thursday, June 11th, 2015 at 2:36 pm
Blind Spot Assist on the Mercedes-Benz CLA

The advanced technology and advanced safety features in the Mercedes-Benz CLA are part of what make it such an attractive car. Starting at just over $30,000, buyers can get behind the wheel of a well-equipped luxury car at a surprisingly affordable price. That price tag also leaves room for many buyers to add useful features and packages, like Blind Spot Assist.

Blind Spot Assist uses radar technology to sense when vehicles enter the driver’s blind spot. When activated, the driver will see a red icon in the side mirror when a vehicle enters the driver’s blind spot. If the driver initiates the turn signal while a vehicle is in a blind spot, an audible alert will sound as well.


Like any piece of technology, Blind Spot Assist on the Mercedes-Benz CLA is not always 100 percent reliable and is not a replacement for safe driving habits. Although it has proven to be a useful aid for drivers time and time again, nothing can replace a manual blind spot check, so it’s important anyone with Blind Spot Assist still uses their mirrors and turns to check blind spots when necessary.

Mercedes-Benz CLA Blind Spot Assist Issues & Solutions

There are a few issues drivers have had with Blind Spot Assist in the Mercedes-Benz CLA, including:

  • Not detecting vehicles in blind spots
  • Detecting vehicles two lanes over
  • Alerting drivers when they exit off the interstate
  • Detecting barriers and other objects on the road

We’ll provide a few possible solutions to these problems below, which we hope will apply to any other issues drivers might have with their Blind Spot Assist.

Read More: How Does Mercedes-Benz Attention Assist Work?

Please note, if any issues persist or the they are occurring frequently, there may be a problem with the system that should be looked at. Schedule a service appointment so we can get your system functioning properly.

The fact is, Blind Spot Assist is a great asset and one that has helped a lot of CLA owners avoid a collision. While a few owners have reported issues and there are occasionally necessary repairs, the great majority of CLA owners have no problems with their Blind Spot Assist throughout the course of ownership.

Not Detecting Vehicles in Blind Spots

Remember, Blind Spot Assist only begins working when you are traveling over 20 mph, so if you’re in a parking lot or in stop-and-go traffic, you probably won’t get the normal visual alert. If you notice your Blind Spot Assist isn’t detecting vehicles at normal driving speeds, go to the necessary menu options to make sure it’s on. If it is, sometimes a quick restart will do the trick. Deactivate the system for a few minutes and turn it back on.

It could also mean the sensors are dirty, preventing the radar from detecting other vehicles. Wipe the sensors clean or visit a nearby Mercedes-Benz dealership to have them properly cleaned.

Lastly, Blind Spot Assist may not recognize small vehicles or motorcycles, so it’s extremely important you are always checking your blind spots and not solely relying on the technology.

Detecting Vehicles Two Lanes Over

This is not necessarily a problem as much as it is a function of the radar. This will more often occur with larger vehicles that are two lanes over, and although it may not be completely necessary, it should prompt you to check your blind spots and be more aware of your surroundings. Even when there is a lane separating you and a semi, you’re both just a lane change away from a potential collision.


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Alerting Drivers While Exiting the Interstate

Although you may have no intention of returning to the highway, Blind Spot Assist will still provide a visual indicator when a vehicle is in a blind spot. The radar doesn’t send alerts based on your driving manuevers, only the location of other vehicles, so this is pretty normal.

Detecting Barriers and Other Objects

Every now and then, Blind Spot Assist may alert you when there is no vehicles anywhere close. In this case, it’s likely picking up other objects, and while that may cause you to check your blind spots a little more often, that’s not necessarily a bad thing!

Let us know if you’ve had other issues with Blind Spot Assist in the comments, or let us know if the system has been great for you since your purchase!

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21 Responses to “Solutions to potential problems with Blind Spot Assist on the Mercedes-Benz CLA”

  1. Penny deVries says:

    My BSA blinks randomly for no reason. About to schedule a service now. They know about this issue but cannot seem to fix it.

    • Corey Malcom says:

      We have the same issue with our GLA 250, which alarms several times a day and occasionally hits the breaks when going under over passes, or through intersections where shadows may be in the area. We have had it into the dealership twice, both times they claimed that they had fixed it and took it on a 22 mile test drive with no problems. Both times the alarm occured within 5 minutes of picking up the car.

      The whole thing is very frustrating and making us question our decision in buying a Mercedes.

  2. Pete Williams says:

    MB blind spot assist sensors should be a recall item, they cannot survive in Midwest states / salt on roadways.

    • Suzanne Kilner says:

      Agree entirely. Canadian dealership reports it as something they’ve seen a “few” times. One would think they should make it past 3 winters…..

    • Denise says:

      Mercedes knows it has a problem with the sensors because they are not covering them with the Certified Car Warranty. I think this is very poor service and I am very disappointed that they will not back their own product. I will never buy another Mercedes when they won’t warranty their known problems. This is my third and last vehicle from them.

      • Ann Cosier says:

        I agree with you comments! my car was $160,000 AUD and has this problem and is driving me crazy…… it constantly goes off maybe 15 times a day no joke!

  3. Mark says:

    I have a 2012 ML, that experienced the blind spot sensor failures that also faulted the cruise control. $2k later and MB installed the upgraded (hopefully weather resistant) sensors and everything is working again. Feels a little painful to pay for a highly optioned luxury vehicle just to have to pay for the sensors to maintain those luxury features. Previously a Toyota driver, very disappointed with the service/recall for MB known issues.

  4. Vince Taylor says:

    2015 E class sedan. The right rear BSA alert goes off randomly (and sometimes repeatedly) for no apparent reason. This can be dangerous at highway speed as it will slow the car rapidly and clench the seat belts tight as if anticipating a collision – all of which can be very disconcerting for anyone not aware of the problem. (It frightened my wife terribly.)

    The dealer has looked at it several times and could not replicate the problem. There were a few stored event codes that read “CB111B00 Radar sensor 2 is disrupted by interference from an external transmitter.” The upshot was that MB does not classify this as a problem.

    2 issues with that. (1) Whether or not they feel is it s problem does not matter – it is a problem when a system in the car goes off for no reason and could possibly cause an accident by catching the driver off-guard. (2) If the error code can distinguish between an external transmitter and the signal it should pay attention to, why cant the system filter the external transmitter out?

    All in all – the handling of this one is VERY un-Mercedes-like – very unsatisfactory.

  5. Don BATES says:

    I have owned at least one MCB at a time since 1969. The last two have been GL350 BTs. These are the worst vehicles I have ever owned of any make. At first I didn’t mind the many problems because of the new technology but since then I’ve learned the manufacturer has been unwilling or unable to make proper changes. I will never have another and will do whatever I can to discourage my friends and encourage any enemies to buy then:)

  6. J. Boonstra says:

    My new, under 4000 KM, 2018 Mercedes blind spot assist is intermittently indicating someone beside me when there are wide open fields. Sometimes for 15 minutes at a time. Of course during these times I also get the audible alert every time I signal to change lanes. Very annoying.

  7. Jo Ann Lampe says:

    I have been having horrible trouble with BSA, it nearly caused me to wreck this Sunday, I never know when it is going to happen, always there is not a car around any where. I have now disabled it and will miss having it when it works, but Sunday did me in, I will be afraid to enable it now.

  8. Bill says:

    I have a CLA 250 year 2017 Blind spot assist works fine. EXCEPT after driving now only 6K miles, the yellow lights in the BOTH mirrors come on when pulling up to a red light. Then they go off around 17 MPH. They never did this for the first 5900 miles Dealership says that is how they are supposed to work. SO why for the 1st 6K miles they never did this?

  9. Yohannes says:

    2014 ML350 4matic blind assist inoperative this issue should be covered by Mercedes with no cost its very frustrating! I’m not happy with manufacture they should fix their issue! if they can’t make it don’t even bother adding it, leave it to the experts!

  10. Bill P says:

    How do you get to the BSA sensor?

  11. Art Speck says:

    This system has failed twice in less than one year for my wife’s MB. Dealer told us if it isn’t replaced the car could loose ALL its power & they wouldn’t be able to start it again!!

  12. Ellen M Courtright says:

    Yohannes – what was your resolution with your ML 350? I have the same issue

  13. Ellen M Courtright says:

    Yohannes – What was your resolution? I have the same issue with my ML 350

  14. Reginald Fennell says:

    I just purchase a 2011 ML 350 and my blind side assist isn’t working either. If this is a know problem and they don’t want to recall it, maybe 9 on your side should take a look at all the compliant and run an investigation to see who’s at fault for selling American’s a defective sensor. I’ll take all your replies and find out what can be done to correct the situation.

  15. Kris says:

    ML350-BSA inoperable since heavy snow fall this last winter🤨Orange triangles just remain lit all the time now, annoying. Almost $2K to replace sensors and was told if I don’t replace them eventually vehicle will not go into park or drive..WAIT WHAAAAT??! That’s insane! Was told it’s part of the whole safety system. Trying to research that cause I haven’t heard that one and dealership that did my last B service didn’t mention that at all. Also figured out once the BSA is inoperable you can not then decide to deactivate it. I agree that these BSA sensors should definitely be a recall. Very disappointed!

  16. Blair says:

    While I don’t have a CLA, I am experiencing the same issues on a 2018 Sprinter. Had it into dealership twice with no resolution. They admit the system is not operating correctly, but maintain that because the ODB system is reporting “everything’s fine” , that they can not fix anything. Frustrating. Disappointing. I came across this thread after seeing it was the highest ranking page when searching for this Mercedes issue.

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