Adaptive Cruise Control Problems of Mazda CX-5

After driving a few mile, the following two warnings come up * Smart brake system malfunction * forward radar sensor system malfunction. If I turn off the car and then restart, the warnings go away. However, it comes back if I drive for a while again. I have visited dealership a few times for the same issue, they replaced the wheel bearing and brake switch. The warning disappeared for days and came back.

See all problems of the 2023 Mazda CX-5 🔎.

When accelerating, the transmission feels jerky/stutters. The check engine light and traction control light are illuminated and on the instrument cluster the messages: "forward Smart city brake support malfunction", "Smart brake system malfunction" and "front radar sensor system malfunction" appear. The vehicle acts like it doesn't know which gear it should be in, it'll buck pretty hard and then it refuses to accelerate. . . It feels like it's in a "limp mode". A previous driver of the vehicle complained and said that it actually stalled in traffic on the highway and was of course difficult to steer due to loss of power. I took it to a dealership and they came up with a laundry list of things to fix. . . Most of which wouldn't have any bearing on this issue. I did have the serpentine belt replaced and the belt tensioner replaced due to wear on the belt and loose tension. On 7/16/25, I scanned the vehicle with a code reader, the codes p0301 and p0506 appeared. P0301 is a generic "cylinder 1 misfire detected" message and p0506 is a generic "iac system rpm lower than expected. The vehicle was taken to a shop where the spark plugs and the cylinder 1 coil was replaces and the iac cleaned. On 7/24/25 the same vehicle behaviors were observed and the same warning lights and messages were activated. I scanned the vehicle and got "p0300 random/multiple cylinder misfire detected and p0304 cylinder 4 misfire detected. There was a recall on this particular vehicle make, model and year and my vehicle was out of the VIN# range. I firmly believe that the recall needs to be expanded to include a larger number of vehicles. . . You can google about this vehicle and see many others with similar issues. Usually, the cure is a pcm reflashing/software update that seems to take care of the issue. Please expand the recall before someone dies in an accident because of this problem.

See all problems of the 2019 Mazda CX-5 🔎.

Will driving on the interstate, using the adaptive cruise control feature, vehicles were slowing down to a stop ahead and my car accelerated instead of slowing down. I then pressed the brake and simultaneously, the car breaks locked down (automatic braking). Unfortunately I wasn’t able to avoid an accident as I rear ended the vehicle in front of me. My vehicle has been turned over to the insurance company to assess damage. I’m sure it can be inspected by NHTSA. Mine and others safety were at risk due to the malfunction of the cruise control accelerating instead of stopping. It caused an accident. Luckily no one was extremely injured. I have neck and back pain from the collision that will hopefully heal in a few days. Time will tell. But this could have been much worse had I not reacted as quickly as I did. This could cause a fatal accident. The care isn’t drivable so it has not been reproduced by anyone. I have notified the insurance company about the issue and it is my hope that they will inspect this. There were no warning lights or messages displayed prior to the incident.

See all problems of the 2021 Mazda CX-5 🔎.

I have a 2024 Mazda Cx-5 but this is in any model and year that has the adaptive radar cruise control. When you set the distance you want to follow the vehicle in front of you, you will go the speed you are going until you come to the space you have set for the vehicle in front of you. Your vehicle will slow to match that vehicles speed. If that vehicle slows down, you will slow down. What it doesn't do it turn on your brake lights so the vehicle behind you knows that your vehicle is slowing down. Sometimes if the vehicle in front of you slows down fast, so does your vehicle. You have no control how fast it does that, it just does it. Now if the vehicle behind you doesn't realize that your vehicle has done this, well it has been very close two times so far. I do not want my new car rearened. I did not know it did this with the brake lights and Mazda doesn't tell you that you have no brake lights when this happens. Why would they have a setup like this. It is like brake checking the vehicle behind you. I do not use my cruise control for that reason. It would be nice to be able to use it on a new car but I do not want to get hurt or get someone else hurt by doing so. I did contact Mazda and they know it does that. This is what they told me "case number 00171326      hello. My name is dominique. I am sorry that you have had some very close calls while slowing down while vehicles were behind you. As for the question you had asked about cruise control activating the brakes when your vehicle starts to slow down, it does not activate the brake lights. It is just like when you are driving without cruise control and you go to take your foot off of the gas pedal instead of using the brake to slow down, it would not activate brake lights either unless you actually mash the brakes, the same with cruise control.  thank you for being a part of the Mazda family.  " isn't that great. I am now a safely hazard or at least my vehicle is, and they are all like that. Who knew. Not me.

See all problems of the 2024 Mazda CX-5 🔎.

Cruise control suddenly ceased operating and I believe that is disabling the automatic collision avoidance system.

See all problems of the 2018 Mazda CX-5 🔎.

I was traveling behind a propane truck, that was going to make a right turn. I disengaged the adaptive cruise control by tapping on the break. I began coasting to a stop, suddenly the car began accelerating again with no warning. I was forced to make the turn with the propane truck and side swiped the truck in the process.

See all problems of the 2020 Mazda CX-5 🔎.

The vehicle continues to have safety features malfunctions with its sensors. The forward facing camera sensor and the blind spot monitoring sensor continues to malfunctions when driving in clear visibility with light to heavy traffic at random times during a day. These features assist the driver to maintain a safe distance from other vehicles while driving. My vehicle has almost crashed several times due to the failures of the features such as the stop and go traffic and forward facing crash detection not working properly.

The adaptive cruise control system (collectively including the lane departure warning, forward collision warning, Smart city brake support etc. ) on this SUV stops working abruptly and randomly while the car is in operation on the road. This is a major safety concern as it can crash into a leading vehicle in absence of adaptive cruise capabilities. The system generally resets or starts working again after a 5-10 minutes, but there is no rhyme or reason why it stopped working or when it would start again. It has happened in cloudy, harsh cold weather, and also on a bright, warm sunny day. This makes the acc unreliable. The dealer could not reproduce the malfunction, as generally the car is stationary in the workshop or isn’t driven for a long enough time while testing.

See all problems of the 2017 Mazda CX-5 🔎.

1st issue - system monitor restarts without warning. Just driving along with only one iphone plugged in the monitor shows a spinning "wheel" saying restarting while driving, 2nd issue - with two iphones plugged in it starts having more issues. Stops charging second iphone connects then reconnects constantly. Then stops (see picture) 3rd issue - with only one iphone plugged in and running navigation from iphone, the system disconnects from iphone but no voice unless we disconnect, 4th issue - while driving in adaptive cruise control and braking for people stopping the cruise control will not re-start. It shows on- keep pressing resume - but will not engage (above 40 mph) then after a few minutes it does respond to the resume command.