ACC disabled in the cold

R

Randy Stegbauer

Member
In Cincinnati for a couple of weeks now it's been in the 30s and below. Just about every time I start it up, the ACC, Brake Assist, and Collision Mitigation are disabled. See below. If I drive it far enough, and then turn it off and back on right away, all of the messages disappear. I suspect that *something* warms up. Has anyone else experienced this?

For example, this morning it was 2 degrees and I drove it four miles to work. Turning it off and back on did *not* remove the messages for that short drive. Later in the day, I drove it 20 miles on the expressway in HV mode part of the time. Once I arrived at my destination, I turned it off an on and then the ACC was enabled (green).

Clarity Dash Cold Brake Alerts.webp
 
I have received that message, but only after driving in the snow and slush, mainly on the interstate where passing trucks throw up all sorts of gunk.

If I am on a short trip, by the time I have parked it in the garage overnight, the gunk has melted and the warning is gone. If I am on a long trip and want my HondaSensing back, I will pull off and wipe the big H on the front grill with a rag I keep especially for the purpose. Then the warning goes away until the big H gets gunked up again.

I have never gotten that error message just because it was 30 degree or less. Otherwise it would be on all the time. Sounds like you either have a dirty H (!!!) or a glitch.
 
I'm sorry. I should have mentioned that the front of the car and windshield were all clean in most if not all of these cases.

I guess I'll be scheduling service to check it out.
 
You may find that the sensors are being effected by the cold weather. Because after the car warms up they eventually start working.
 
neal adkins said:
You may find that the sensors are being effected by the cold weather. Because after the car warms up they eventually start working.
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Yes, that's my current theory. I'm guessing that the "radar" behind the grill Honda logo is used for both the ACC and Collision Mitigation. Does anyone know anything about this sensor and if low temperatures can make it fail?
 
It's cold again in Ohio, so I'm starting to see this again when I first start up the car when the temperature is (maybe) 20F or lower. Does anyone else see this?

The ACC and Collision Mitigation is disabled until I drive the car about five miles and then turn it off and back on.

Thank you,
Randy Stegbauer

index.php
 
Make sure the Honda badge on your front grille is clean. Your Clarity's radar system is behind it. If anything, it would seem that the radar system would get colder after you start driving. In three Michigan winters of driving our Clarity PHEV, I've never seen that warning except when the H was covered with road goop.
 
I wonder if your big 'H' has a hairline crack in it, allowing cold damp air to get inside the radar sensor?

What did the dealer say when you took it in early last year?

I've driven mine in 20F weather, using ACC without any warnings.
 
Cincinnati has been cold most of this week, so it's been failing almost every morning and I finally had Honda look at this. After two visits they are going to replace the radar unit. It threw code P2583-96, which is titled, "Millimeter wave radar internal electronic failure". The mechanic said he "checked the connections", but I didn't get to talk to him of course, so I don't know exactly what that means. I probably should have simply disconnected and reconnected the wiring harness myself to see if that would be enough.

Searching for the code or description doesn't lead to any extra information. I'll take that as a good sign, meaning that appearantly no one else has seen this problem so the new radar unit won't have the same issue.
 
I had a similar experience but it was while driving. Someone got in the gap between myself and the front car. Sprayed quite some water which froze on the sensor.

Also, ACC tried to follow tire marks when it rains and had to turn it off on rainy days.


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Some of you mention using ACC in the rain or snow. Not only does it not work as well in these conditions (like any cruise control) but its not a good idea. You should be ready and alert for varying conditions, not just cruising, at least till full autonomy comes along.
 
laptop said:
Also, ACC tried to follow tire marks when it rains and had to turn it off on rainy days.
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ACC isn't capable of "seeing" tire marks or ruts in snow - I think you might be thinking of LKA, which does use a visual sensor and looks for lines along the road to keep the car in lane.
 
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