Stop / start traffic and using ACC, every now and again it senses the car in front, slows down but when it gets to around 1 mph and about 3ft from car in front, it disengages and accelerates.

Has worked flawlessly in 6k miles.

Conditions are warm, dry and sunny. Car is very clean with no instructions.

Will see how it fares tomorrow.

SS is also on BTW.

I experienced that a couple of weeks back in light rain. It hasn't done it again even in the same conditions. I almost wondered if it just needed the car to be shutdown and rebooted? Mine does occasionally restart the engine when a vehicle ahead of the one in front moves before the one directly ahead.

I'm trying to work out if it is a particular model as I have noticed it seems to be Fords only, and the recent ones have been new model Focus.

So here's a thought......are they fitted with radar based self parking/anti-collision systems on the same radar frequency block (it is likely to be a common frequency system like 2.4GHz WiFi which shares with all sorts of Industrial, Scientific and Medical devices 'in band' ) and affecting the ACC on mine to an extent it 'loses lock'? Wifi uses spread spectrum systems specifically to avoid interference. Do our radars?

Having checked, these systems all use 77-79GHz depending upon country, and are licence exempt (in the UK at least) so assigned on a free-for-all basis as long as they meet the right spec. These systems must not cause interference to other services but have to put up with interference from in band users! It is therefore possible that it could be another radar upsetting the systems in ours.

Edited 4 May, 201610 yr by FelisBengalensis

I thought it was something to do with the vehicle in front at first - it was a matt black wrapped BMW 3 Series, possibly the matt finish causing some sort of interference. But I then later switched lanes and was following a Skoda Fabia of all things, the ACC continued to play up.

 

I managed to completely switch off the car and restart during the traffic jam, but left the ACC off until we got clear of the jam. It performed normally after this but wasn't tested in a bumper to bumper situation.

Appears to be all back to normal now.

Used it yesterday with no problems.