2017 CX-5 Radar cruise control intermittently disabled below 20mph

Yep, this is how the MRCC behaves in my car as well, and from what I've read this is the correct behavior.
Chaisu said:
I have had my 2017 CX-5 GT for about 2 weeks now and this error showed up a few days ago. Before this error started I could set cruise control as long as I'm going above 20mph, and as long as I would do that MRCC would go all the way down to 0 mph. When it came to a complete stop it would autohold by itself even if you don't have autohold switched on. When the car in front of you begins moving again you lightly tap the accelerator and the MRCC will resume.
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This sounds like there is a problem with your MRCC...at least according to the manual and videos depicting how the system is supposed to work. I'd report it to Mazda as they may have a software glitch that needs fixing.
Chaisu said:
...Now I get the same error message as the OP and when I initiate MRCC (above 20mph) and my speed drops below 20mph the car beeps at me and flashes the error message on the HUD as well as info gauge.
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As far as how/when the system is used. Well, I use it on the freeway or highway (basically any mostly straight, typically fast-moving stretch of road). As all of us Californians have come to realize, that highway can turn into a parking lot very quickly. And in that scenario, the MRCC can come in very handy.
 
mocx-5 said:
I've gotten the error with auto-hold enabled and disabled, but I'm pretty sure that setting is independent of the stop and go cruise functioning. I'm using it on my highway commute, which is typically ~50-70mph but can be stop and go some days. The message will show right away when I enable the cruise control but sometimes it doesn't show up at all. At first I thought it was an obstruction of the camera (which runs the cruise under 20mph), but there's actually a distinct message for that, which tells you to clean/defog your windshield.
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Did you ever hear back? I'm getting the same error with mine. Happens as soon as I start the car. If I turn if off and on again, the error sometimes goes away. Dealer isn't all that convenient to drop off at right now so I'm curious if anyone here knows of a solution. No idea why people feel like this error with the car is the right time to preach about when people should/shouldn't use cruise is, though.
 
It's not preaching, people are just advising when it should actually be used as per Mazda's advice
 
Buzzman12 said:
I don't understand people using their cruise control in stop and go traffic and thinking they've got an autonomous vehicle.
This isn't a self driving car. It's not Tesla folks.
Cruise control is just that: cruise control. It's not a substitute for driving in city traffic.
(yes I know, I'm preaching.)
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If it were advertised and worked well for the purpose, why wouldn't people use it that way? Are you saying that functionality wouldn't be something good, or just that people are confused and misguided if they think that that level of functionality is promised and ready?
 
Buzzman12 said:
I don't understand people using their cruise control in stop and go traffic and thinking they've got an autonomous vehicle.
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Here's what's wrong with that statement:

If someone uses their cruise control in stop and go traffic, it does NOT imply that they think they've got an autonomous vehicle.

No one thinks it's a Tesla.

They are not "substituting" cruise control for "driving".

It's a useful tool, if it used properly. If you can't figure out a good way to use it, don't use it. But realize that some can.
 
Tesla is not supposed to call their system autonomous. Relying on these systems without maintaining vigilance is what gets a driver into a situation.
 
Make sure your windshield and sensor up front are clean. For the sensor I used Sonax Brilliant Shine Detailer as it is very hydrophobic and repels rain and dirt much better. I even wiped the rear camera lens with it so rain drops don’t stay.
 
It’s “stop and go”. So I use it in stop and go traffic. Works great, be smart and drive defensively and vigilantly.
I enjoy the member’s comments and top notch knowledge here but - Jeeze, we’ve got some old ladies here.
 
From the user manual:

"Do not use the MRCC with Stop & Go function system in the following locations, using the MRCC with Stop & Go function system at the following locations may result in an unexpected accident:

  • General roads other than highways (Driving under these conditions using the MRCC with Stop & Go function system is not possible.) Roads with sharp curves and where vehicle traffic is heavy and there is insufficient space between vehicles.
  • Roads where frequent and repetitive acceleration and deceleration occur (Driving under these conditions using the MRCC with Stop & Go function system is not possible).
  • When entering and exiting interchanges, service areas, and parking areas of highways (If you exit a highway while headway control is in use, the vehicle ahead will no longer be tracked and your vehicle may accelerate to the set speed).
  • Slippery roads such as ice or snow-bound roads (Tires could spin causing you to lose vehicle control, or the stop hold control may not operate.)
  • Long, descending slopes (to maintain distance between vehicles, the system automatically and continuously applies the brakes which could result in the loss of brake power.)
  • Slopes with a steep gradient (The vehicle ahead may not be detected correctly, your vehicle may slide while stopped by the stop hold control, and it may accelerate suddenly after it starts moving.)"

As per the first point, if you want to use it in normal day today traffic, then use it at your own risk
 
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I use it because it allows me to use cruise control in our residential areas which have a speed limit of 30kph. Normal cruise doesn't work at this speed. One thing I've noticed is that it correlates to the auto brake hold not engaging. It just flashes the light a couple times but then the light stays off. I see auto brake hold as an issue that prevents the low speed cruise from working so I'm thinking brake hold is the root issue. Not sure why though. Guess I'll have to get the car in to a dealer to check out.
 
cdaling said:
I use it because it allows me to use cruise control in our residential areas which have a speed limit of 30kph. Normal cruise doesn't work at this speed. One thing I've noticed is that it correlates to the auto brake hold not engaging. It just flashes the light a couple times but then the light stays off. I see auto brake hold as an issue that prevents the low speed cruise from working so I'm thinking brake hold is the root issue. Not sure why though. Guess I'll have to get the car in to a dealer to check out.
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From my readings, MRCC won't allow auto hold to work
 
I can verify that MRCC and auto hold are totally compatible. I have MRCC on at all times [not necessarily active, but always enabled], and usually turn on auto hold. If I approach a stopped vehicle too fast, I get a warning. Even got one today.

What amazes me is that it works so well. There are plenty of times that it might be fooled or inappropriate [RTM], but those are times that you wouldn't engage standard CC either. But I have never gotten an inappropriate false alarm.
 
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