[leftoverture]

Our 2016 228i convertible only has 38k miles, and it has never caused us any concern until today. I left work at about 5pm, it is very hot and humid in our area right now. I put the top down (because that's what convertibles are for!) and pulled out on the road. Got up to speed, about 55-60mph, and maybe 1/2 mile down the road I feel a jolt and the car goes into limp home mode. I think the jolt was the car downshifting as it went into limp mode. I turned around, pulled back into work, shut the car off. Then restarted it and all was fine and I drove home without issue. No error lights showing. I haven't scanned for codes yet, but I'll get to that. I'm thinking just an electrical glitch, maybe due to the heat /humidity, but curious if anyone else has had a similar experience.

[harma24]

I went out to mow my lawn tonight and experienced a similar issue. Half way though my allergies kicked in big time and the heat and humidity made me want to shut down too, but a good swift kick in the rear kept me going.


As for the car, I've only had it go into limp mode once; got on the highway on a snowy morning and felt that vibration indicative of snow/ice packed in the wheel. The car decided that it didn't like it. Pulled off the highway, cleared the snow and all was good. But I can point to a definite cause. I'd be concerned if there was no warning ahead of time and nothing that you did to resolve the issue.

[MarcoZandrini]

Originally Posted by leftoverture

Our 2016 228i convertible only has 38k miles, and it has never caused us any concern until today. I left work at about 5pm, it is very hot and humid in our area right now. I put the top down (because that's what convertibles are for!) and pulled out on the road. Got up to speed, about 55-60mph, and maybe 1/2 mile down the road I feel a jolt and the car goes into limp home mode. I think the jolt was the car downshifting as it went into limp mode. I turned around, pulled back into work, shut the car off. Then restarted it and all was fine and I drove home without issue. No error lights showing. I haven't scanned for codes yet, but I'll get to that. I'm thinking just an electrical glitch, maybe due to the heat /humidity, but curious if anyone else has had a similar experience.

These cars go into the limp mode to protect the transmission and/or engine from damage. You need to get the engine computer (DME in BMWspeak) and the transmission computer (EGS) scanned for codes.

[leftoverture]

At this point I'm viewing it as most likely an electrical/computer glitch. It's sitting at home today but I'll see how it is next time I have it out.

[Shovelman]

Is there a switch that indicates that the top is down and secure? If so it may have bumped open which you would hope would put you into limp mode.

[jzeiler4]

I doubt that was it as if you exceed the 35 mph while moving the top, the only thing that happens is the top stops moving.

[leftoverture]

Well, it's been a few more days of driving and not even a hint of another problem. It seems more and more like one of those odd glitches today's modern electronics seem to have every now and again.

[aerobod]

Originally Posted by leftoverture

Well, it's been a few more days of driving and not even a hint of another problem. It seems more and more like one of those odd glitches today's modern electronics seem to have every now and again.

One cause of random chip errors are bit flips due to high energy cosmic rays. In most cases either error correction in memory DIMMs themselves or at a software level will handle the error. This Google study estimated approximately 4,000 cosmic ray bit flips per DIMM module per year: https://static.googleusercontent.com...hive/35162.pdf