[cmyx6go]

Originally Posted by Efthreeoh

To really clarify the purpose of the warning. The warning is used to warn the driver there may be black ice on the road left over from overnight even after the air temperature has warmed above freezing. There can be locations on the road where the sun or air has not melted black ice on the road even though ambient air temps are above freezing. So, if the air temp near the surface of the road goes below 37 deg. F when the ambient air temp is above 37 the alarm triggers.

If you notice, the warning does not come on if the car is first started in air temps below 37 deg. It comes on only once the car measures temps above 37 then drops back down below 37 deg.

Mine chimes when I start it if the temp is below 37 degrees. I have no problem with the chime as it alerts to possible ice on the road like others have said.

[Tambohamilton]

Originally Posted by cmyx6go

Mine chimes when I start it if the temp is below 37 degrees. I have no problem with the chime as it alerts to possible ice on the road like others have said.

+1, mine bongs at startup if temp is below 3C, and it will bong any time on that journey if the air temp crosses from above to below 3C.

[tracer bullet]

Yeah, me 3. Any cold start, even in my garage 1st thing in the morning, if it's cold it bongs at me. The methodology mentioned might be true of newer cars.

I don't mind it, it's kind of a subtle reminder to not go hooning around when tire grip is low.

[Efthreeoh]

Originally Posted by cmyx6go

Mine chimes when I start it if the temp is below 37 degrees. I have no problem with the chime as it alerts to possible ice on the road like others have said.

So, after I wrote that I drove the E90 that morning. I was going to double check it. It was below 37, but my car has a few other audible warnings come on at engine start (brake fluid service is past due and the SOS/Bluetooth) the also snowflake pops up after the other warning icon clear, so the snowflake warning may be being obfuscated by the other two. So, my 60+year memory failed me. I stand corrected.

But regardless, per the few different BMW manuals (my E30 is first where I read the detail about the warning) states what I wrote regarding the black ice warning. The E90 states it as:

"When the displayed temperature sinks to approx. +37F/+3C, a signal sounds and a warning lamp lights up. There is an increased risk of black ice. Black ice can also form at temperatures above +37F/+3C. You should therefore drive carefully on bridges and shaded roads, for example, otherwise there is an increased risk of an accident."

The "shaded road" one once showed me, on a road I used to drive on every day, how well the BMW stability control works. The ice warning came on just as I entered a very tight turn, in the shade, in the winter, and next to a valley of creek I had just dropped about 100 feet down into. Pucker factor pegged the needle.