ACC issue

[Spivvy]

Has the strangest problem today with ACC it was bouncing between 70 and 40 as I was driving along
Even with ACC off you could see the speed limiter moving up and down
Anyone else seen this

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[SRGTD]

Is this the old mph and kph confusion issue that seemed to affect a number of early examples of current generation VAG cars that share current generation software?

That was an early software gremlin where UK mph speed limit signs were being misinterpreted by some cars as kph. 70 kph is 43 mph, so pretty close to your indicated 40 figure. Maybe a recent software update has ‘unfixed’ the fix that corrected this issue?

 

[bounderboy]

What software are you on OP?

 

[Spivvy]

What software are you on OP?

1890
Had the car 14 months never had this issue before


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[ozzrahog]

Is this the old mph and kph confusion issue that seemed to affect a number of early examples of current generation VAG cars that share current generation software?

That was an early software gremlin where UK mph speed limit signs were being misinterpreted by some cars as kph. 70 kph is 43 mph, so pretty close to your indicated 40 figure. Maybe a recent software update has ‘unfixed’ the fix that corrected this issue?

Mine has started doing this, not a bad as the original fault where it would show the speed limit sign in km/h

 

[Spivvy]

Restarted the car and all back to normal

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[vmaxkiddy]

Mines done it twice. Set 70 which dropped to 44 mph, set 60 dropped to 34 and 27mph. Car slams the anchors on to reduce speed. F ing dangerous. I’ve videoed it but can’t seem to post that here.

 

[bounderboy]

Mines done it twice. Set 70 which dropped to 44 mph, set 60 dropped to 34 and 27mph. Car slams the anchors on to reduce speed. F ing dangerous. I’ve videoed it but can’t seem to post that here.

That is scary - Can you upload to YouTube and link it here?

 

[DEAN0]

Mines done it twice. Set 70 which dropped to 44 mph, set 60 dropped to 34 and 27mph. Car slams the anchors on to reduce speed. F ing dangerous. I’ve videoed it but can’t seem to post that here.

You can go in to the settings and tell the car NOT to react to posted speed limits.
This way it will not slam on the brakes - it will just maintain the speed you set.

 

[Veni]

You can go in to the settings and tell the car NOT to react to posted speed limits.
This way it will not slam on the brakes - it will just maintain the speed you set.

Ditto that. I’ve never had the ACC set to obey road signs and it has been fine. I changed it to obey the speed limits and the car started changing to speeds that were not even the same as the speed showing on the road signs.
So I switched it back to ignoring posted speed limits and it’s fine.
I do get the screen showing random speeds in the road sign detection but it doesn’t affect the ACC… only when this happens, it won’t let you overtake anyone as it seems to think you’re in a left-hand drive trying to undertake. Annoying as that is, the only remedy is to tap the throttle to override it.

 

[DEAN0]

it won’t let you overtake anyone as it seems to think you’re in a left-hand drive trying to undertake. Annoying as that is, the only remedy is to tap the throttle to override it.

If you have or know someone with OBDeleven - you can code out this overtaking on the left issue.

 

[KevinW]

Mines done it twice. Set 70 which dropped to 44 mph, set 60 dropped to 34 and 27mph. Car slams the anchors on to reduce speed. F ing dangerous. I’ve videoed it but can’t seem to post that here.

Mine is doing exactly the same, bloody dangerous. It's not linked to road signs at all and sat nav stated 70mph. Car behind got a shock when my car slammed all on at 70mph to 44mph.

 

[dashnine]

I've just moved to a new house, and nearby is an A road with average speed camera zones starting at 30mph, then 50mph, then 40mph, then 60mph and finally 70mph.

I thought it'd be a good idea the link the camera road sign recognition and the ACC, and it was OK for a couple of trips but in another trip it flipped the 50mph to 31mph (thinking 50kph) and the other equivalents, as above.

But it happens randomly, not like it's spotting a repeater speed limit sign and then flips back to 50mph. Most bizarre, it';s almost as it the two ECUs are arguing... After a (unprompted) infotainment restart it's fine again - for a while I assume!

 

[vmaxkiddy]

The ACC mph/kmh confusion on my car has now been cured. The infotainment complete unit (screen etc) has been replaced and a new unit fitted which had to be coded at the factory before being sent to the dealer.

 

[Karbonfaiba]

The ACC mph/kmh confusion on my car has now been cured. The infotainment complete unit (screen etc) has been replaced and a new unit fitted which had to be coded at the factory before being sent to the dealer.

Interesting, could you tell us what system information says about Display Unit/control panel hardware now?

Would you know what it was before the unit was replaced?