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Adaptive Cruise Control (ACC) does not work anymore.

julekasMobilek

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Location
Vilnius, Lithuania
Car
honda accord
The problem is in ***le.
Last year (or last few months) ACC was woring OK, after that it sometimes throws notification (ACC OFF) when i tried to set the speed, and now it always says ACC OFF when i try to set the speed.

What gives?
No check engine light ar no check ACC light, this evening i will try to hook up HDS trough usb, but i think there also will be no errors. Any help?

My car is tourer, diesel, executive with LKAS and NAVI
 
If you’re able to book with me I’ll be able to diagnose any issues with the system
 
Reading through loads and loads of threads someone mentioned the most stupid idiotic idea of checking the tyre pressure is correct. My ACC would set and unset itself then check system would light up on dash. Annoying more than anything especially with the number of speed cameras round here. I pumped up all four tyres to the correct pressure and unbelievably the most idiotic suggestion actually worked!!! Thank you to the person who posted it. Today's lesson in life, never look for the most expensive solution try the most idiotic cheap fix first.
 
Wonderful!! Actually makes sense, not idiotic at all.
 
Wonderful!! Actually makes sense, not idiotic at all.
I now know that fahad but it was something so simple it's the sort of thing you overlook. I read stories of Honda wanting £200 just to diagnose then £1100 for a new radar with no guarantee it would solve the problem
 
Just out of interest how low did the pressures drop? as I've had low pressure on one or more tyres and never had any check lights or acc disabling itself. I too have acc and lkas and dread the day something goes wrong with it as it would be pricey to put right, probably end up just doing without if the radar or control units went
 
Just out of interest how low did the pressures drop? as I've had low pressure on one or more tyres and never had any check lights or acc disabling itself. I too have acc and lkas and dread the day something goes wrong with it as it would be pricey to put right, probably end up just doing without if the radar or control units went
Hi
Hsak1981, nsr and osr were 28 and 32 nsf was 33 osf was 34. It had been stood since I was kicked out of the office 13 weeks ago for lockdown so apart from driving my allowed 5 miles a day to keep engine lubed and the tyres round, I have neglected keeping on top of weekly checks. From 180 miles a day to and from work down to 5 miles a day is amazing for the fuel consumption but not good for the car.
 
I've had pressure differing similar to what yours were and it didn't upset the cruise control strange. Only thing I can think of if it was definitely the pressures was the rear corner at 28 was making the front of the car point up slightly at an angle upsetting the radar. Hopefully it'll not need any more attention
 
Hello guys, i have tried a new mayle brake switch - the problem does not go away.
I hooked up HDS - no errors, what so ever.

ANd yet, when i trie to set speed in cruise, it just throws notification: ACC OFF.

Here is my video:

there is no "error" per say, like a orange or red light, just notification "ACC OFF", i ***ume that this ACC OFF is triggered when certain signal is present.
Right now i cannot test what event triggers acc off notification, maybe you guys can?
Try to set speed, and then press brake pedal, clutch pedal, horn, does your also throws acc off?
 
Can I just check is your car is remapped at all? I’ve seen this before with incorrect software calibration.
 
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So yes it’s remapped or no it’s not? And if it is, did this problem start after or was it always there?
 
This may help. It's the same system as mine with lkas and adaptive cruise control.
Maybe the cancel bottom on steering wheel is faulty and it's switching it off or maybe it's one of the other things it talks about
 

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So yes it’s remapped or no it’s not? And if it is, did this problem start after or was it always there?
I got this car for almost 5 years. During this 5 years period i did not went to remap shops or what so ever, and yes ACC was working fine. After 2 years it began to degenerate. ACC OFF throws once in about 10 trips. And right now ACC OFF throws on every trip.

As you can see in my video at around 0.10 / 0.11 timestamp it show briefly "120km/h", indicating, that is set this speed limit, but after that it also cancels and throws ACC OFF.
Right now i did not see this anymore, it immediately throws ACC OFF.

This may help. It's the same system as mine with lkas and adaptive cruise control.
Maybe the cancel bottom on steering wheel is faulty and it's switching it off or maybe it's one of the other things it talks about
Thank you very much! As i can see in the second page i got exactly "Automatic ACC cancellation" every time i try to set the speed.
 
Might be as simple as the cancel button is stuck on cancelling setting as soon as you try and set it. I can't remember ifc the display shows 'ACC OFF' when pressing cancel, I'll try and remember to check for you next time I'm in car. The fact that are no errors showing up on HDS leads me to think something is happening that's meant to cancel it like one of the senarios mentioned in the handbook.
 
I dont think that cancel button is the problem. Because when you press cancel there is no long beep and ACC OFF on the screen, please duoble check if you can on the road :)

> the vehicle speed below 25km/h - obviously, not an option
> poor weather conditions - how does it sense it? in the winter i got CMBS radar with hand logo yellow, so this is also not an option
> grille radar dirty - not the same as previous one?
> the vehicle ahead of you cannot be detected - same as above?
> abnormal tyre condition/skidding - interesting, how does it sense it?
> mountain or offroad driving for long periods -?
> abrupt steering wheel movement - not an option, because when i jank the steering wheel LKAS immediatelly let go of lanes. so working ok.
> ABS or VSA is activated - not an option
> trailer stability ***ist is activated - does this comes as standart? I do not have trailer hitch.
> ABS or VSA indicator comes on - not an option

manual trans:
> ignorint to shift up/shift down - when i got working ACC, this feature was working (also as is clutch pedal switch A and B), when i held clutch IN for a period of time, it throws ACC OFF. but when i do normal shifts, it was ok, ACC was able me to shift up/down and did not lose the set speed.
> redline - not an option.
> below 1k rpm - not an option
> press and hold clutch for a while - not an option, same as ignoring to shift up.
> shiftin into N - not an option

after this lift i am down to:
poor weather condition, dirty radar (maybe behind the bumper?
abnormal tyre condition / off road / mountaint driving?
 
I would double check tyre pressures. It senses it probably due to car leaning towards tyre that is low affecting the radar aim. If the rear of the car sits low the radar would point up and vise versa. But maybe the radar is dirty behind the bumper might be worth having a look and clean and also behind the badge. Also maybe remove the connector to the radar unit making sure car is definitely off then plugging back in
 
Btw I've just noticed this thread isn't visible on the list under technical board then 8th gen accord. Only way I can find it is if I look in my alerts. The threads are listed in date order under regular threads with this being 16th June and it's not there. So you might not get much help with the problem if thread not getting seen.
 
It’s being seen as far as I can tell.
 
Sorry my bad it's under 8th gen then faults dunno, I couldn't see it for looking at it.

Are you any further on with it?
 
Hello guys, i just wanted to update my current sitaution of not working ACC.
Since CSAK1981 posted some guildlines of ACC off message, i have decided to fix my suspension bushings, because it has some free movement, i bought them:2020-07-07 20.05.31.jpg
But i haven't got time to fix this, press out and press in new poly bushings.

Anyway during some trips in the city my clutch pedal started to act strange it was not smooth, when pushed fully clutch in, i heard strange 'bong' noise, and pedal dropped half way, I though, that some sort of spring snapped. Still clutch was ok, i can engage and disengage it, but pedal travel was very short. After few trips pedal got back to top and again it seemed okay. Very strange.

I searched trough internet new clutch master cylinder, but there are no aftermarket parts, so i went full original in Honda dealer. It cost ~260euros and 50euros labor.
I got my car back yesterday and pedal travel was perfect and smooth, and the best part, that ACC started working perfectly since then, now during testing i try to set speed even going above 40 km/h, and it still works, no ACC OFF message yet!

So... what gives?
 
Clutch pedal switch faulty?
Did the new CMC come with the switch installed or maybe just the act of breaking the connection and remaking it was enough?
Let me know how you find the Siberian bushings, I was looking at them but ended up going for complete TRW branded arms, seems good so far, I still have to fit the rear adjustable ball joints as my camber is still negative 2°each side.
 
Yep clutch pedal switch most likely original cause
 
Clutch pedal switch faulty?
Did the new CMC come with the switch installed or maybe just the act of breaking the connection and remaking it was enough?
Let me know how you find the Siberian bushings, I was looking at them but ended up going for complete TRW branded arms, seems good so far, I still have to fit the rear adjustable ball joints as my camber is still negative 2°each side.
strange enough, in our land, especially honda, does not look any further than the problem itself.
here is invoice of the job:
CMC;
brake fluid dot 4, 0.3L
and labor 0.7 hour

nothing more.

honda.jpg


i got siberian bushings from official website. Had to pay tax'es because they came from mother russia :(

i do not believe that clutch sensors were faulty, especially they are two sensors :?
 
Hello guys, fitted with poly bushings in my 8gen accord:
8393522010c280063e2c32646bdf3923.jpg

84ca94eb0799407ebc41462bd03820dd.jpg
 
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