Rear Traffic Alert on our 2018 CX-5 No Longer Working!

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2018 CX5
Hello. Today I noticed that as I was pulling out of a parking space I did not get the usual alert when a car passed behind me. Tested it at home with having someone walk behind as I was in reverse and no alert. The rear camera works fine.

Has this happened to others? Is it common for the rear traffic alert to stop working? Anything to check as a cause?

Thanks!
 
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Go check settings in HMI, sometimes (rare) it can lose the setting.

r1.png
Settings can be changed by operating the centre display screen.
Smart City Brake Support Reverse (SCBS R) The system can be changed so that Smart City Brake Support (SCBS) does not operate.*1
 
So, I went into the Settings and turned the Safety/Radar control systems off and then back on. That seemed to do it (testing in the parking lot, the car alerted me when a car was passing behind).

But, it still does not alert if a person is behind the car but come to think of it, it never did. Does your CX5 give an alert if you are backing up and someone is standing behind you?
 
2016 CX5 here, it usually does when some one is walking by, not just standing.
 
So, I went into the Settings and turned the Safety/Radar control systems off and then back on. That seemed to do it (testing in the parking lot, the car alerted me when a car was passing behind).

But, it still does not alert if a person is behind the car but come to think of it, it never did. Does your CX5 give an alert if you are backing up and someone is standing behind you?
Mine does as "madar" wrote
 
Mine will alert sometimes if there's somebody walking by. I think it depends on how fast they're moving, how big they are, etc.
 
But, it still does not alert if a person is behind the car but come to think of it, it never did. Does your CX5 give an alert if you are backing up and someone is standing behind you?
In my experience with a 2020 it is a motion detector that does not alert for stationary objects. So a standing pedestrian wouldn't cause an alert. I've found it reliable in picking up walking people with the occasional exception which I can't account for.

It never squawks about a stationary vehicle when backing up out of a parking spot, even into the warning zone on the rear view camera. I've not tried backing toward a stationary pedestrian though I'm confident I'd run him over waiting for an alert.

Under the heading of "go figure", the general section for Radar Sensors (Rear) at page 4-215 in the 2020 manual suggests it will flag stationary objects which it does not. The specific section for Rear Cross Traffic Alert at page 4-143 discusses only vehicles in motion with no mention of pedestrians, consistent with the name of this system, when it fact it will flag them when walking (most of the time). The only mentions of pedestrians in the manual relate to the front camera functions.

Anyway, if you're not getting alerts for walkers check the bumper for crud, ice or snow which can mess with detection. Also, if the bumper is deformed you may be SOL, though in that case you'd probably get a BSM OFF indicator for a blind spot detection system error, BSM being the other function that uses the rear radar.
 
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Interesting. On our 2018 there are no visible radar "buttons" on the bumper to check. I guess they are hiding behind the rear bumper??
 
Interesting. On our 2018 there are no visible radar "buttons" on the bumper to check. I guess they are hiding behind the rear bumper??
2018 Manual:


The 2023 manuals show the same thing so it's probably the same for years in between.

I presume the positioning of the radar units high on the bumper and angling away from the vehicle allows them to do double duty--they are also the blind spot warning sensors.

One other note. Check out the diagrams in the following 2018 link, especially the 4th. diagram where two vehicles are backing directly into each other:.


There is a radar dead spot directly behind the middle of the vehicle. So I would expect a pedestrian walking directly toward the rear hatch handle likely would not be picked up.

The 2023 manual shows the same thing, so again probably the same for in between years.
 
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Interesting. On our 2018 there are no visible radar "buttons" on the bumper to check. I guess they are hiding behind the rear bumper??
Yes, 2 radar sensors used for Blind Spot Monitoring System (BSM) and Rear Cross Traffic Alert (RCTA) are hidden behind the 2 corners of the rear bumper.

Those “buttons” on rear and / or front bumpers you can see are Parking sensors, front and rear. On CX-5 Signature they’re integrated into the infotainment system.
 
On my 2016 CX-5 GT, RCTA can only detect slow-moving vehicles (metal objects), not pedestrian-capable. The same (not pedestrian-capable) on my Smart City Brake Support (SCBS).
 
On my 2016 CX-5 GT, RCTA can only detect slow-moving vehicles (metal objects), not pedestrian-capable. The same (not pedestrian-capable) on my Smart City Brake Support (SCBS).
It's weird that the 2020 manual makes no reference to pedestrian detection for rear cross traffic alert. That hasn't changed in the 2023 manual.

I'm not alone in having observed rear cross traffic flagging pedestrians. I specifically recall this happening a couple of times in the Walmart parking lot flagging people walking by with no moving vehicles in the vicinity. It's happened with people not pushing carts if a cart might be picked up as a vehicle. I guess I'd call it an Easter egg. Perhaps Mazda found it to be insufficiently reliable to mention it--if it works in a particular situation, good, if it's doesn't that's on you the driver.

Some time between 2016 and 2020 SCBS became Advanced SCBS "in some models" which includes pedestrian detection:


I had to pull out my Monroney label to see it my vehicle has the Advanced version--it does--since I've not threatened a pedestrian so far. I can think of few I wouldn't mind testing it on. ;)
 
Yes, 2 radar sensors used for Blind Spot Monitoring System (BSM) and Rear Cross Traffic Alert (RCTA) are hidden behind the 2 corners of the rear bumper.

Those “buttons” on rear and / or front bumpers you can see are Parking sensors, front and rear. On CX-5 Signature they’re integrated into the infotainment system.
My Blind Spot system seems to be working fine so since it uses the same sensor as the RCTA system, I guess the rear traffic alert is just for traffic and not people.
 
That’s why I always find a double empty spot and pull through so that I don’t have to back out of a crowded parking lot. I hate that people no long pay attention when their walking, just keeping their faces glued to their phones.
 
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