Whilst driving up the A10 this morning I got the warning beep and the Maxidot indicated a fault with the ACC: "ACC sensor has no view", or something similar.

 

Curious, I stopped at the next lay-by and found a leaf sitting in front of the ACC radar - unlucky or 3 months of ACC warnings to come?

I never had anything like that in 14 months of ACC on my Audi. There is a similar crisp packet myth that goes around though...

I never had anything like that in 14 months of ACC on my Audi. There is a similar crisp packet myth that goes around though...

 

Maybe I was just unlucky then. (I don't actually believe the crisp packet story btw)

The only time I've had that error has been in an extremely intense downpour and it went away after 20 seconds.

Thought the rader was in the bumper, Is there an opening for it?

Thought the rader was in the bumper, Is there an opening for it?

 

It's in the lower grill, open to the eliments, soon to fill up with snow

I have problems with snow on my Passat cc. Seems to build up on the radar and block the view.

The references to heavy rain/snow has got me thinking, is the ACC coded to alter it's behaviour depending on the weather? Is the gap to the car in front increased in the rain? Or is it coded for the worst possible case, with loads of margin in perfect conditions?

 

Anyone know?

 

ps - I'm not sure snow and ACC are a good match.

I imagine any adaptive system like this, the amount of radar data that get returned to the sensor will dictate the size of the gap between the vehicles,  rain and snow will disapate the signal that returns, in good conditions more of the signal will be returned.

I had a similar message on my maxidot telling me to clean my front window because the camera couldn't see for the light assist. To be fair it hadn't been cleaned for a month though.

I read somewhere that the radar emitter/sensor face is heated to prevent icing - very smart. I wish I had it on my VRS.

Reminded me of something that I had read in the hadcopy Car mag: VW Golf GTI (2014) long-term test review of Mk7 GTI

"On the subject of auto braking, the Golf also has Front Assist, a forward-facing radar that detects obstacles; plus City Emergency Braking, which slams on the anchors for you if you fail to respond. The other day I was crossing an empty junction when the front brakes suddenly engaged so violently, I almost head-butted the windscreen. I think the radar detected a pothole, and thought I was driving over a cliff."

I don't have ACC so cannot comment.  It might have been a leaf or a crisp packet of course...