2017~2021 Radar cruise control intermittently disabled below 20mph

mocx-5

Member
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2017 CX-5 Grand Touring
I have a brand new 2017 CX-5 Grand Touring with stop and go cruise control. About 50% of the time I use the cruise control, I get this message: "Mazda Radar Cruise Control Disabled under 20 mph". The radar faceplate and the camera are both clean (I get a different message when they are obstructed). The dealership has checked the computer and found no errors or faults. There doesn't seem to be a pattern as to when it's disabled and when it's not, so I'm having trouble diagnosing.

The manual (page 4-126) says this message displays when there is an issue with the forward sensing camera, an issue with the stop hold control function, or the electric parking break.

Any ideas?

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GJ-Molestor

Banned
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2011 BMW 528i, 2015 Mazda 6, 1995 Nissan Maxima Manual
most adaptive cruise control systems don't work below a certain speed, so I would chalk it up to that but it doesnt seem to be the issue in this case.

does the cruise control work fine at higher speeds?
 
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'18 Mazda CX-5 Akera KG i-Activ AWD 2.5L In Sonic Silver
most adaptive cruise control systems don't work below a certain speed, so I would chalk it up to that but it doesnt seem to be the issue in this case.

does the cruise control work fine at higher speeds?

Mazda's is as follows:

The Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) system operates when all of the following conditions are met:
Vehicle speed is 0 km/h (0 mph) to 145 km/h (90 mph)
 
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2019 CX-5 GT 184 2.2 twin turbodiesel auto - Sonic Silver
I don’t have it but looking at this detailed info it would seem to me that although it has stop and go, it won’t reliably maintain operation at low speeds so it drops out. So, it will stop and go on the motorway but if you start crawling in traffic it hands back to the driver.

Makes sense to me. You’d have somebody reading Facebook on the freeway before so long.
 
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'18 Mazda CX-5 Akera KG i-Activ AWD 2.5L In Sonic Silver
I don’t have it but looking at this detailed info it would seem to me that although it has stop and go, it won’t reliably maintain operation at low speeds so it drops out. So, it will stop and go on the motorway but if you start crawling in traffic it hands back to the driver.

Makes sense to me. You’d have somebody reading Facebook on the freeway before so long.

I think not all the conditions are being met, hence the malfunction
 

mocx-5

Member
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2017 CX-5 Grand Touring
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.
 

mocx-5

Member
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2017 CX-5 Grand Touring
Oh, and yes, to be clear, the cruise works fine above 20mph (when the radar is running things, not the camera). If I'm reading the manual right, the issue may not be with the camera at all, though. My working theory is a software issue of some kind that fools the car into thinking the camera or the break isn't working correctly. My dealer was stumped (they'd never even seen the error before). They're going to follow up with the Mazda rep so I'll post here if I get any more info. But anyone else experiencing this and noticing any patterns would be helpful. The sales guy who sold me the car owns the identical 2017 model and has been getting the message, too, so I'm pretty sure it's not an isolated thing.
 
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'18 Mazda CX-5 Akera KG i-Activ AWD 2.5L In Sonic Silver
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.

Auto hold does impact mrcc, so best to have it off during mrcc use
 
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2018 CX-9AWD GT
Oh, and yes, to be clear, the cruise works fine above 20mph (when the radar is running things, not the camera). If I'm reading the manual right, the issue may not be with the camera at all, though. My working theory is a software issue of some kind that fools the car into thinking the camera or the break isn't working correctly. My dealer was stumped (they'd never even seen the error before). They're going to follow up with the Mazda rep so I'll post here if I get any more info. But anyone else experiencing this and noticing any patterns would be helpful. The sales guy who sold me the car owns the identical 2017 model and has been getting the message, too, so I'm pretty sure it's not an isolated thing.

So are you trying to initiate cruise control below 20MPH? I've never tried that personally, but I thought the intent was for the cruise to be initiated at higher speeds and then if you slowed or dropped down to zero it would continue and bring you back up to the set speed. I think you just need to be moving a bit faster in order to initiate the set speed? According to page 4-155 of the manual "With cruise control, you can set and automatically maintain any speed of more than about 25 km/h (16mph)."

Sounds to me like you just need to speed up a bit.

EDIT: FYI that page reference is from the 2018 CX-9, so the CX-5 page may be slightly different.
 
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Chaisu

Member
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2004 Honda Accord EX
So are you trying to initiate cruise control below 20MPH? I've never tried that personally, but I thought the intent was for the cruise to be initiated at higher speeds and then if you slowed or dropped down to zero it would continue and bring you back up to the set speed. I think you just need to be moving a bit faster in order to initiate the set speed? According to page 4-155 of the manual "With cruise control, you can set and automatically maintain any speed of more than about 25 km/h (16mph)."

Sounds to me like you just need to speed up a bit.

EDIT: FYI that page reference is from the 2018 CX-9, so the CX-5 page may be slightly different.

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.

I had been using MRCC like this with no issues in stop and go bay area traffic with speeds ranging from 0-35 mph. It worked great for me at the time. 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.