"Drive moderately. Apply additional braking when necessary. Consult nearest service center."

[808Pants]

That was my center-screen alert earlier today. It cleared on its own after about ten minutes.

If this isn't spurious, then does it indicate pads, fluid, or... that the car doesn't appreciate my normal driving style?

 

[mojo]

It seems like it's telling you that regenerative braking might not be working correctly (without actually using those words, which some users wouldn't understand)? Was your battery SOC at 100%? We know that regenerative braking doesn't work as effectively until there is space in the battery for the regen energy to go (and the car is supposed to use the friction brakes instead to compensate) - but I've been in that position on my car many times, and never seen that message.

If you don't intend to take it to a dealership for diagnosis, you may need to have a look at it yourself with Bimmerlink (or similar) and see if any DTCs have been logged?

 

[808Pants]

It seems like it's telling you that regenerative braking might not be working correctly (without actually using those words, which some users wouldn't understand)? Was your battery SOC at 100%? We know that regenerative braking doesn't work as effectively until there is space in the battery for the regen energy to go (and the car is supposed to use the friction brakes instead to compensate) - but I've been in that position on my car many times, and never seen that message.

If you don't intend to take it to a dealership for diagnosis, you may need to have a look at it yourself with Bimmerlink (or similar) and see if any DTCs have been logged?

Thanks Mojo. SOC was moderately high, but not nearly full up. A month or so ago, I was again wondering about what you're describing - I then had it up to 136 miles after re-genning down the long volcanic slope known locally as the "Saddle Road," between two volcanoes on the big island of Hawaii. The next morning I continued down the slope and had no similar complaints...IIRC the available miles kept going up until we ran out of "downhill."

I *do* need to connect again - haven't done so since I exchanged a WIFI dongle for a wired ethernet version, having found the WIFI was objectionably slow. And yes, I'm very late in forking over the $50 or whatever for B-link. Gonna get on that within the next few days.

But I've also never change fluid or inspected pads (fluid level is OK, at least). 47K miles, as I recall.

 

[mojo]

I'm in a similar position with Bimmerlink - got Bimmercode, but not needed to check any codes, yet...

If you're on 47k miles I would be tempted to changed brake fluid or at least have it tested for water content. If for no other reason than to reduce the chances of corrosion within the brake system components.

I don't think the message can relate to worn pads -- if that is the cause, I'm fairly sure that the car displays a more specific message than the one you are seeing.

 

[alohart]

A month or so ago, I was again wondering about what you're describing - I then had it up to 136 miles after re-genning down the long volcanic slope known locally as the "Saddle Road," between two volcanoes on the big island of Hawaii.

That's a pretty long descent. I don't know what the maximum regen power is, but it might be the same as the maximum propulsive power, 125 kW although it doesn't feel that strong. In propulsive mode, 125 kW can be maintained for only 30 seconds before something begins overheating (maybe the uncooled motor rotor) at which point the propulsive power is reduced to 75 kW. In regen mode, even if less than 125 kW, maybe similar overheating occurs eventually at which point regen braking power is reduced. The warning tells you to use the friction brakes more than expected. However, why would the message recommend consulting a service center when normal operation would return upon cooling as it seems to have done in your case? Oh, well, it's fun to guess.

I *do* need to connect again - haven't done so since I exchanged a WIFI dongle for a wired ethernet version, having found the WIFI was objectionably slow.

What have you used with a wired Ethernet connection? I know of ISTA, but I don't believe that BimmerLink works with a wired Ethernet connection. Having used ISTA a bit with its wired Ethernet connection, the OBD port or the electronic modules in the car might be the speed bottleneck, not transmitting the data via WiFi or Ethernet.

 

[Dutchi3]

We know that regenerative braking doesn't work as effectively until there is space in the battery for the regen energy to go (and the car is supposed to use the friction brakes instead to compensate) - but I've been in that position on my car many times, and never seen that message.

I now live on top of a hill, and the regen works fine going down the hill -without use of the friction brakes- when I leave with 100% charge (which is in reality less than 100% due to a top end buffer). I rather think that you have less/no regen when the bms decides that the pack is too cold to receive full regen at higher charge levels. In other words, it is probably temperature dependent how regen at full battery behaves. In Holland, when the temperature was close to freezing, on a flat road the friction brakes would assist in the first mile, when the battery was at full charge. The regen power is limited to 50kW, which corresponds to the max. DC fast charge power. The difference is that full regen is available even with a full battery, while in a DC charging situation the power is tapering off when exceeding 80% charge. So at what temperature do you experience this behavior? The motor and electronics have no issue delivering a constant power of 50kW even under sustained periods, as the nominal power of the motor is 75kW.

The only thing that is strange to me, in the situation described here, is the displayed message. Never saw that one, even when the car had limited regen due to low temperature.

 

[mojo]

So at what temperature do you experience this behavior?

Not particularly cold at all. I really only notice it a short distance from my house, where there is a steep(ish) downhill section. I think I know when the car is substituting friction for regen, because I hear a scraping noise at the back where the disks are slightly rusty, even though I'm not using the footbrake. Last time I noticed it, the temperature was probably around 15 degrees (so a few months ago now).

But... I might be wrong, and attributing a noise from somewhere else as brake noise. And it probably does it at other times, but I don't hear because it's cold and I have the windows wound up!

 

[808Pants]

I now live on top of a hill, and the regen works fine going down the hill -without use of the friction brakes- when I leave with 100% charge (which is in reality less than 100% due to a top end buffer). I rather think that you have less/no regen when the bms decides that the pack is too cold to receive full regen at higher charge levels. In other words, it is probably temperature dependent how regen at full battery behaves. In Holland, when the temperature was close to freezing, on a flat road the friction brakes would assist in the first mile, when the battery was at full charge. The regen power is limited to 50kW, which corresponds to the max. DC fast charge power. The difference is that full regen is available even with a full battery, while in a DC charging situation the power is tapering off when exceeding 80% charge. So at what temperature do you experience this behavior? The motor and electronics have no issue delivering a constant power of 50kW even under sustained periods, as the nominal power of the motor is 75kW.

The only thing that is strange to me, in the situation described here, is the displayed message. Never saw that one, even when the car had limited regen due to low temperature.

Thanks, Dutchi3 - but "cold" to us here in Hilo means low 60s F. Interesting angle, though. I'm gonna have to watch and see if it recurs, but timing for observations isn't great, since visiting bro means we had to rent a larger vehicle through the holidays while the i3 sits forlorn in the garage. Perhaps it will learn its lesson.

I'd been thinking that every possible warning/advisory/etc had been catalogued and discussed here, but apparently I found one that's not made the rounds. This leads me to wonder: wouldn't BMW have something akin to a glossary of these messages for just this kind of event? I mean, my i3 didn't author that warning; some engineer did, so it seems it must have been intended as the "then..." part of an if/then statement.