Cruise/ACC not working: two beeps, ACC OFF error

[squidge]

This started 350 miles into a 500 mile road trip yesterday. 2018 Clarity PHEV, 1,950 miles. First time stretching its legs since I bought it a few weeks ago.

Cruise control will not engage in ACC or standard mode.

Main is on, dash displays ACC/LKAS. Trying to set ACC results in two short beeps and ACC OFF on the dash.

Switching from ACC to standard cruise by holding the distance button, standard cruise will not engage either.

Turning ACC off/on using the Main button or power cycling the whole car does not fix the issue. I turned the car off/on three times and it's still happening.

I gave the Honda badge sensor a wipe down, turned LKAS/collision mitigation off and back on, that stuff all seems to work fine.

Any ideas?

 

[Tek_Freek]

From:https://www.verneidehonda.com/honda-adaptive-cruise-control-acc/

How do you reset Adaptive Cruise Control?
In order to reset Honda’s ACC system, simply press and hold down the interval button (vehicle with four bars behind it) for approximately one second and Cruise Mode Selected will appear in the instrument panel. Press and hold the interval button again to reset the Adaptive Cruise Control feature.

 

[squidge]

Thanks, but as I stated, I tried that.

 

[Tek_Freek]

Hmmm.... Still don't see where you said that.

 

[Frankwell]

Switching from ACC to standard cruise by holding the distance button, standard cruise will not engage either.

In order to reset Honda’s ACC system, simply press and hold down the interval button (vehicle with four bars behind it) for approximately one second and Cruise Mode Selected will appear in the instrument panel.

Pressing and holding the interval button merely switches from ACC to regular cruise, and back again. The local dealer instructions that you linked to for some reason used the word "reset" to describe this, instead of saying "switching" which is how most people would refer to it, as does the owners manual.

 

[jdonalds]

I doubt if any of these are your problem but they are things not already on your list.

1) Cycle/Reset the audio system on the info screen by holding the Home button for more than a few seconds. Yes this is just the audio system but it seems to have been used to cure some things other than audio.

2) Is it possible your radar is blocked. I've never had it happen but people have reported that snow or mud on the Honda emblem on the front of the car can cause the system not to work. I'm guessing you might get a clear message though such as "clean the radar screen".

3) How about disconnecting the 12V battery and reconnecting it.

Just a hunch but I'm thinking this is something that can be reset rather than repaired.

I hope you find the solution.

 

[Tek_Freek]

Pressing and holding the interval button merely switches from ACC to regular cruise, and back again. The local dealer instructions that you linked to for some reason used the word "reset" to describe this, instead of saying "switching" which is how most people would refer to it, as does the owners manual.

Thanks!

 

[Tek_Freek]

Thanks!

Did you hold it a second time? Pressing once for 1 second does one thing. When you hold it a second time it resets.

 

[Frankwell]

This started 350 miles into a 500 mile road trip yesterday. 2018 Clarity PHEV, 1,950 miles. First time stretching its legs since I bought it a few weeks ago.

Cruise control will not engage in ACC or standard mode.

Main is on, dash displays ACC/LKAS. Trying to set ACC results in two short beeps and ACC OFF on the dash.

Switching from ACC to standard cruise by holding the distance button, standard cruise will not engage either.

Turning ACC off/on using the Main button or power cycling the whole car does not fix the issue. I turned the car off/on three times and it's still happening.

I gave the Honda badge sensor a wipe down, turned LKAS/collision mitigation off and back on, that stuff all seems to work fine.

Any ideas?

In the owners manual it lists the usual suspects like dirt on the badge, but interestingly it also mentions issues with the wheels including tire pressure and suspension. Although it doesn't say if there would be any warning messages or if it would just not set. I'm guessing that you did not get a TPMS message but as a longshot you might check your tire pressures.

 

[Frankwell]

This started 350 miles into a 500 mile road trip yesterday. 2018 Clarity PHEV, 1,950 miles. First time stretching its legs since I bought it a few weeks ago.

Cruise control will not engage in ACC or standard mode.

Main is on, dash displays ACC/LKAS. Trying to set ACC results in two short beeps and ACC OFF on the dash.

Switching from ACC to standard cruise by holding the distance button, standard cruise will not engage either.

Turning ACC off/on using the Main button or power cycling the whole car does not fix the issue. I turned the car off/on three times and it's still happening.

I gave the Honda badge sensor a wipe down, turned LKAS/collision mitigation off and back on, that stuff all seems to work fine.

Any ideas?

In the owners manual it lists the usual suspects like dirt on the badge, but interestingly it also mentions issues with the wheels including tire pressure and suspension. Although it doesn't say if there would be any error messages or if it would just not set. I'm guessing that you did not get a TPMS message but as a longshot you might check your tire pressures.

 

[sabasc]

It's possible an OBD2 scan might help. There are threads here about obtaining the Bluetooth devices and software we used (topic: troubleshoot air conditioning condenser failures in our Claritys, resulting in warranty extension).

 

[pigrew]

The service manual states:

When the ACC is activated, if the multipurpose camera unit determines that the ACC is unable to operate normally due to an environmental factor (such as weather or road surface condition and driving or vehicle condition) or other reasons even when the ACC system itself is normal, the multipurpose camera unit automatically cancels the activation of the ACC and records the ACC system auto stop control code in it.

When the ACC is automatically cancelled, ''ACC OFF'' is displayed on the multi-information display (MID) to notify the driver of the cancellation. At this time, the ACC indicator (amber) does not come on.

The system stores the last 10 reasons that ACC is turned off, but you'd need the Honda computer to read out what the cause is.

Try cleaning the windshield in front of the front camera (center top of windshield) and and checking that the brake pedal switch works (does the rear brake light turn on when the brake pedal is pressed)?

Other causes could be bad yaw-rate sensor, bad 12V battery, bad radar, or even "extensive driving on a rough or winding road". Most should give a DTC, so checking for DTC is a good idea.

 

[squidge]

Thanks, everyone. Tire pressures are correct, badge sensor is clean (although the windshield is somewhat dirty which I will try). I have an OBD2 reader somewhere, and I will see if I can pull DTCs from it. Very helpful to know that the reason the ACC did not engage is stored. I also have a service appt with Honda on Friday so we will see what they say. I drove the car again last night and reproduced the problem -- it hasn't worked a single time since this began.

Randomly, I went to change the cabin filter last night and found that the original has been chewed up and was full of mouse turds, so I'm hopeful that this is not a chewed wire situation. I still have about ten days to return the car to Carmax, so the results of the Honda visit will likely dictate whether I keep it or not.

As for pulling the battery cable to reset the car, I've worked in IT/software engineering for many years and the one thing I don't want to do is make the car lose state and start working again, when nothing has actually been solved. Better to keep the problem reproducible until the dealer can look at it.

 

[MrFixit]

I have an OBD2 reader somewhere, and I will see if I can pull DTCs from it.

From my experience, a random OBD2 tool (with some kind of App) will not see any of the ACC information. It is too deep in the bowels of Honda-Land. Then, on the other hand, we have found that the AP200 (possiblly with the Beta Honda update) could have some utility.

Here is a snip from one of the AP200 modules ("Integrated Driver Support"):



Note that there is a history of ACC 'cancelations' as described by @pigrew
I have no entries in mine, and can't speak to what it would mean if there were entries, however... I did some googling and found this reference to how to interpret entries (if they were to appear here):



I don't know if this would reveal anything in your case as to a cause or not... But, as I mentioned, I don't think you can even query this information without a more 'professional' scan tool (or an AP200).

If I were you, I think I would try the 12V battery reset... If it is a persistent problem, then it won't go away and you are off to the dealer. If it goes away, there is a good chance that the 'reset' was actually a 'fix'. Just keep in mind that resetting the 12V battery will light up a whole bunch of dash lights / warnings that will go away after driving for a short while. It is a little scary, but many have done it with no ill effects.

 

[squidge]

Thanks. I actually just did a 12v battery reset about a week ago when I installed a Civic Touring leather-wrapped steering wheel, and encountered all the warning lights until I did a short drive, so I'm not afraid of that.

However I'm a little apprehensive about resetting it again and having this issue return later, since I only have about ten days to return the car to Carmax or about two months until their limited warranty is up. Through Honda, I'm not sure if this issue would fall under the bumper to bumper (expired) or powertrain warranty, but I'm really more focused on figuring out the root cause in the slightly longer term than on "fixing" it right now via a reset and having it return later when I would have to pay out of pocket for repairs. Especially since I only use ACC on trips and don't have anything planned for a while.

Really appreciate all the input about the scan tool, good to know.

 

[MrFixit]

Thanks. I actually just did a 12v battery reset about a week ago when I installed a Civic Touring leather-wrapped steering wheel, and encountered all the warning lights until I did a short drive, so I'm not afraid of that.

Now that you mention that again - I am highly suspicious of the non-standard steering wheel. After all, the ACC is totally controlled from there.
Are you sure (did you already say) that the ACC never worked right from the start (before you even touched the steering wheel)?

If it turns out to be related to the steering wheel, then certainly Honda would not be inclined to cover it under warranty because a "modification" was done !!

 

[squidge]

It's a good point, but what I did is a pretty well-documented upgrade: https://ngnpenn.blogspot.com/2019/12/clarity-leather-steering-wheel-upgrade.html

I did not have any problems before the steering wheel change. However I also had the ACC work totally fine for 350+ miles after the steering wheel change. And the swap is very straightforward -- there really isn't anything about it that could've introduced flaky behavior. And it is a genuine Honda part of the exact same design.

If I get to a point where the problem is undiagnosable I would certainly consider swapping the stock rubber wheel back in as a control.

 

[insightman]

I went to change the cabin filter last night and found that the original has been chewed up and was full of mouse turds

You're not alone. Here's a thread on this forum you will find interesting: What's in Your Cabin (Filter). I hope you have photos you can contribute to this thread.

Honda learned an important lesson with the 2000 Honda Insight and they no longer use tasty soy-based insulation on the wiring in their cars. Mice totaled my friend's gen-1 Insight, but I was luckier. Of course, vermin are wont to eat wiring, tasty or not, but at least Honda's not encouraging it anymore.

 

[squidge]

Disconnected the battery, swapped the rubber steering wheel back in, reconnected the battery and took it for a drive. Cruise still does not work, same behavior with two beeps and ACC OFF. Switching between ACC/cruise mode and back by holding the distance button ("resetting") makes no difference.

If this was a one-off problem I'd pursue a fix, but given the cabin filter with mouse droppings, and unknown future issues, I'm returning the car to Carmax and getting a Honda CPO 2021 I found at a dealer, 7k miles, for about a thousand dollars more. Pleased that I can still have a Clarity -- fingers crossed this one works out.

 

[squishycans]

Huh, so I've been having a problem where I hit set and the display above the steering wheel says "Cannot Set Cruise: Slope Too Steep". But after hooking up an OBDLinkMX+ and checking the yaw sensor, the z-axis (grav) appears to be reporting correctly (so no slope condition from the sensor), so I thought I would try it again and see what happens.

Now it is doing exactly what yours was doing - displays nothing and just turns off immediately. Very odd. I did a battery reset, tried toggling between cruise and ACC, and I tried taking to the dealer twice, but for some reason it starts working for them (I saw it with my own eyes). I really wish Honda would allow us a service manual so I could figure this out (the dealer won't do anything because they couldn't confirm anything). All I have gathered is that the Honda symbol is a radar sensor, there is a yaw sensor (somewhere...), and the ECU seems to be interfacing everything and acting as the Cruise Control Module (which is right next to the battery, so maybe I'll try replacing the ECU with an ebay one). I guess the ECU is suspect.

What the heck? Has anyone else had this issue? Does anyone know of a good resource that will show me where all the parts involved in the cruise control are? And any wiring diagrams for this?

Also, the OBD2 sensor I have doesn't read ACC problems unfortunately. If anyone knows how to do this, I'd highly appreciate any advice on the matter.

edit: Actually, I'm a dumb-dumb. It's not reading the yaw sensor - it was just showing my phones sensors...probably is the yaw sensor.