Dashboard displays 2 malfunctions in cold weather

[SteveBrickNJ]

When they weather is cold, my 2020 CX-9 dashboard displays: "Front Radar Sensor System Malfunction" and "Smart Brake System Malfunction". Yet if I drive my 2020 CX-9 on a warm part of the day those 2 messages do not display. I have an oil change scheduled at a Mazda dealership in a week. I don't want them to fool me into an expensive repair when this is just potentially a GLITCH?? Please give advice or best guesses. Thank you! Steve

 

[ADS-B]

I get the same messages when I drive into the sun at sunrise or sunset. It's just a glitch. When you get this messages you won't be able to use the adaptive cruise control.

 

[SteveBrickNJ]

I get the same messages when I drive into the sun at sunrise or sunset. It's just a glitch. When you get this messages you won't be able to use the adaptive cruise control.

Do you predict the dealership can Un glitch me and do whatever is needed without adding to the cost of my oil change and front brakes bill?

 

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Do you predict the dealership can Un glitch me and do whatever is needed without adding to the cost of my oil change and front brakes bill?

There is nothing you can do, honestly. You just have to ignore it. There is nothing wrong with the car. It's the sunlight projecting on the sensor at a specific angle and upsets the system, causes the malfunction message. If the mechanic is honest, he should tell you the same thing. You're not the first one having this malfunction code, he must have had numerous complaints about this issue.

 

[SteveBrickNJ]

There is nothing you can do, honestly. You just have to ignore it. There is nothing wrong with the car. It's the sunlight projecting on the sensor at a specific angle and upsets the system, causes the malfunction message. If the mechanic is honest, he should tell you the same thing. You're not the first one having this malfunction code, he must have had numerous complaints about this issue.

Although I am grateful for your posts, it can't have anything to do with sunshine. Right now it is 8am, cool and raining. No sunshine but the 2 things are displayed. I think the glitch is temperature related, not sunshine related.

 

[sm1ke]

You can ask them to check for the issue during your oil change. They should check their service database for this concern, and if there is an existing TSB for it, they will follow the diagnostic steps to continue troubleshooting.

In my case, I do get this warning occasionally, but it usually happens when there's a bit of frost on the windshield. I wonder if there is frost also forming on the radar sensor and causing the same issue? Again, something you can bring up with the dealer.

 

[SteveBrickNJ]

You can ask them to check for the issue during your oil change. They should check their service database for this concern, and if there is an existing TSB for it, they will follow the diagnostic steps to continue troubleshooting.

In my case, I do get this warning occasionally, but it usually happens when there's a bit of frost on the windshield. I wonder if there is frost also forming on the radar sensor and causing the same issue? Again, something you can bring up with the dealer.

TSB...technical service bulletin ?

 

[sm1ke]

TSB...technical service bulletin ?

Yep, technical service bulletin

 

[youri]

The frost on the windshield or direct sunlight would trigger the camera sensor error message and not the Front radar system malfunction error. They look similar but the messages identifies which sensor is at cause.

The Radar is in the Mazda emblem at the front of the car. If it is dirty it can trigger the error message (for example it happened to me when there was a thick coat of slush on it in a bad winter day). First step I would take is make sure the front of the emblem is clean. (No dirt, bug, ice, etc).

I have also seen where these malfunctions are triggered by low brake fluid level or worn brake pad (due to be replaced). Think of it has the « Smart brake system malfunction » triggering the radar warning instead of the radar triggering the brake system warning. If your brake pads are worn or brake fluid low at your oil change, i would get those done first before touching the radar, because it may fix the issue.

It may be a bad radar sensor or a bad connection, but they are not too common.

 

[SteveBrickNJ]

The frost on the windshield or direct sunlight would trigger the camera sensor error message and not the Front radar system malfunction error. They look similar but the messages identifies which sensor is at cause.

The Radar is in the Mazda emblem at the front of the car. If it is dirty it can trigger the error message (for example it happened to me when there was a thick coat of slush on it in a bad winter day). First step I would take is make sure the front of the emblem is clean. (No dirt, bug, ice, etc).

I have also seen where these malfunctions are triggered by low brake fluid level or worn brake pad (due to be replaced). Think of it has the « Smart brake system malfunction » triggering the radar warning instead of the radar triggering the brake system warning. If your brake pads are worn or brake fluid low at your oil change, i would get those done first before touching the radar, because it may fix the issue.

It may be a bad radar sensor or a bad connection, but they are not too common.

Well ( thanks to you ) we may have hit upon it? I am on the verge of 60,000 miles and I haven't had any brake work done. This Tuesday I was already going to ask the dealership service center to focus on the brakes even before the system malfunction messages ever appeared. Now having read your mentioning the brake fluid being potentially low and the pads being potentially worn....those things being linked to the dash message would make sense.
Thanks!

 

[MichalP]

Just to add another piece of information. I do get this malfunction warnings at times and in my case it is always related to temperature changes and humidity - it usually happens around this time of the year - west coast of Canada - rainy and sudden temperature drops - my guess - condensation is the culprit here. It does not really block the sensors but just "annoys" them. Once I start driving it goes away after a few minutes.

 

[SteveBrickNJ]

Just to add another piece of information. I do get this malfunction warnings at times and in my case it is always related to temperature changes and humidity - it usually happens around this time of the year - west coast of Canada - rainy and sudden temperature drops - my guess - condensation is the culprit here. It does not really block the sensors but just "annoys" them. Once I start driving it goes away after a few minutes.

Ok. IF the brake fluid was the problem, would the sensors messages display ALL the time? My sensor messages are always on (in the recent 2 weeks) during my morning commute....but ONLY SOMETIMES on in my late afternoon commutes.

 

[MichalP]

Ok. IF the brake fluid was the problem, would the sensors messages display ALL the time? My sensor messages are always on (in the recent 2 weeks) during my morning commute....but ONLY SOMETIMES on in my late afternoon commutes.

When you start driving - does the warning go away eventually or does it stay all the the time?

 

[youri]

I am not sure. I don’t think we can say for sure it is the brake fluid or not, other than to say that it may be it. When it happened to me because of the brakes it was intermittent.

Could also be battery related, if it is 5 year old it might be getting old and low when it is cold in the morning and it sat all night, and recharged by the end of the morning commute. Most people replace it at around that time.

But like i said before it could also be a bad radar sensor. I recommend you get the rest in order (brakes if needed, battery if needed, etc). If it solves the issue great, if not then further diagnosis by the dealer or an independent mechanic.