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C400GT serious safety issue

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nikolas

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Oct 28, 2023
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Hi guys,

i own a C400GT 05/2023 with 1800km on the clock. A couple of days ago, while i was riding at ~40km/h entire scooter went dead. Lights, tft display and engine cut off without prior warning or notice. For about 10 minutes it wouldn't turn on no matter how many times i tried, and after approximately 10 minutes, power came back, lights, tft, and engine started running.
I thought i would ride it back to home and arrange it to take it to the garage later on, but 100meters away from where it went dead, it ... went dead again!
I had no other choice, so i arranged it immediately to be taken to official dealer garage.
It stayed 3 days at the garage, and the feedback that i got was that there was an error logged regarding a sensor that has to do with bike having fallen, although it had never fallen in the past. They performed an update because they said there was an instruction to do so and delivered the bike back on Friday.
On Friday, returned home everything was ok.. Today, i started the bike and after a couple of seconds dead again!!

On Monday morning it will be taken again to the dealer, but this is getting quite worrying now.
Any thoughts, or insight would be much appreciated.
 
Too simple a thought I'm sure but --- have you/they checked the battery cables/connections? This happened to me on my new-to-me 650 Sport with only 1960 miles on the clock, and it turned out to be a loose connection at one of the battery poles.
 
@nikolas: Just to confirm, when you say, "Today, i started the bike and after a couple of seconds dead again!!" were you giving it throttle, as if to start riding? These scoots (I'm on my second C 400 GT now) have to warm up for a half a minute or so, before you start off, or they may stall (I'm talking about a previously cold engine).

Other than that, I find it difficult to believe that a malfunctioning tip-over sensor (that's what they're generally called, in the USA, anyway) is the culprit, but who knows. Did you hit any VERY LARGE bumps in your recent riding?

Did you watch them do any of the work, by any chance? They would have at least had to take off the battery cover, for instance, if they checked anything.
 
Hi @wspollack this stall issue has happened to me as well, but this is not the case here. I started the engine, didn’t open the throttle and entire bike went dead as if I had pressed the central lock button. Screen dead, lights off engine dead.
I haven’t hit any large bumps in general not to mention lately and since it is quite new still I m a little extra careful.
Unfortunately I wasn’t able to stay over there and watch the entire process as I had to be at work.
I am thinking of two potential issues that I m with similar propability in my eyes. First is central lock switch acting up (keyless model) or general ECU issue.
 
nikolas said:
Hi @wspollack this stall issue has happened to me as well, but this is not the case here. I started the engine, didn’t open the throttle and entire bike went dead as if I had pressed the central lock button. Screen dead, lights off engine dead.
I haven’t hit any large bumps in general not to mention lately and since it is quite new still I m a little extra careful.
Unfortunately I wasn’t able to stay over there and watch the entire process as I had to be at work.
I am thinking of two potential issues that I m with similar propability in my eyes. First is central lock switch acting up (keyless model) or general ECU issue.
Click to expand...
Well, I hope you get the problem resolved quickly. I have nothing to suggest to you (I liked the battery-cable suggestion by @Ceesie76).

I was without my '22 C 400 GT for five months this year, after the engine self-destructed to some degree. As I reported elsewhere a week or two ago, BMW replaced my bike with a new '23 C 400 GT, so I certainly feel your pain, can empathize with you, regarding not having a perfectly functioning bike.

Good luck.
 
wspollack said:
@nikolas: Just to confirm, when you say, "Today, i started the bike and after a couple of seconds dead again!!" were you giving it throttle, as if to start riding? These scoots (I'm on my second C 400 GT now) have to warm up for a half a minute or so, before you start off, or they may stall (I'm talking about a previously cold engine).
Click to expand...
Hi Bill. I've recently noticed the warmup being necessary and don't like it one bit. Do you know why this is the case? I would think and hope that BMW had considered air fuel management in such a way to prevent this. My seat is getting replaced under warranty and I was going to have them diagnose this issue. Is the warmup requirement published that you saw or just our shared experience?
nikolas said:
Hi guys,

i own a C400GT 05/2023 with 1800km on the clock. A couple of days ago, while i was riding at ~40km/h entire scooter went dead. Lights, tft display and engine cut off without prior warning or notice. For about 10 minutes it wouldn't turn on no matter how many times i tried, and after approximately 10 minutes, power came back, lights, tft, and engine started running.
I thought i would ride it back to home and arrange it to take it to the garage later on, but 100meters away from where it went dead, it ... went dead again!
I had no other choice, so i arranged it immediately to be taken to official dealer garage.
It stayed 3 days at the garage, and the feedback that i got was that there was an error logged regarding a sensor that has to do with bike having fallen, although it had never fallen in the past. They performed an update because they said there was an instruction to do so and delivered the bike back on Friday.
On Friday, returned home everything was ok.. Today, i started the bike and after a couple of seconds dead again!!

On Monday morning it will be taken again to the dealer, but this is getting quite worrying now.
Any thoughts, or insight would be much appreciated.
Click to expand...
Nice to see you here Nikolas. Sorry to hear that this is not resolved yet (I was following your story on the FB forum). I really wish BMW would publish their electrical diagrams as it would be much easier to understand what may be going on with the bike. Electrical problems can be one of the most challenging to diagnose and then of course repair. If the bike is not powering up, it is definitely electrical (I know stating the obvious just driving home why it would be nice to have the diagram). Thanks for sharing this. As crappy as it is for you, I am looking forward to this getting resolved for you and learning more.
 
Today took it to the dealer again. He was surprised to see me entering the garage at such short period of time and with the bike on a tow truck.
They said they would contact BMW centrals for feedback on how to proceed with checks/ replacements and will be in touch with me.
 
mzflorida said:
Hi Bill. I've recently noticed the warmup being necessary and don't like it one bit. Do you know why this is the case? I would think and hope that BMW had considered air fuel management in such a way to prevent this. My seat is getting replaced under warranty and I was going to have them diagnose this issue. Is the warmup requirement published that you saw or just our shared experience?
...
Click to expand...
It's just my experience -- maybe too early in the mornings for me, with my brain still foggy -- that I started the bike and almost immediately start off, and a couple of times the bikes have stalled. I can't find anything in the manual about that, so I now purposely let it idle for a minute. Never had the problem when the RPMs are at warmed-up idle speed, which, for me, on both the '22 and '23, is a flip-flop between 1400 and 1500.
 
wspollack said:
Speaking of early mornings, I just noticed this. What's the issue with the seat?
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Cosmetic. They did not tighten the side fabric adequatley and it is puckering. I am particular and thought I might be nit-picky presenting it as a concern. BMWNA approved it in just one day so I guess they agreed! @wspollack 2023-10-30_18-08-02_081.webp
 
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Although it is not related with the current topic, I had the same feedback from dealership a couple of months ago regarding a question about the necessity of warming up for a minute or so just to let oil go through entire circuit.
 
Still no news! They haven’t been able to find the issue. They are thinking possibly the alarm module to be causing the issue but haven’t been able to confirm it.
 
nikolas said:
Still no news! They haven’t been able to find the issue. They are thinking possibly the alarm module to be causing the issue but haven’t been able to confirm it.
Click to expand...
That is actually interesting. We don't have the alarm on ours here in the USA, to the best of my knowledge. That makes sense though as the alarm probably has an ignition cutoff to prevent it from being ridden away.
 
Small update, they deactivated alarm to have it tested it for a while (~5 days). Nothing similar occured since then, until.. today, that it would refuse to unlock for around 20 minutes.. until it decided to unlock and ride back home.
 
Took it to the dealership again, after the previously described incident, they plugged it in for fault check and there was a fault in the communication between immobilizer and keyless. Now I m waiting for their feedback on how they are going to handle this
 
Small update again.. Bike still at the dealership, they spotted signs of moisture in one of bike's ECUs so they are waiting feedback whether to replace the specific part, and if any actions need to be taken regarding the prevention of moistrure (re)appearing on the ECU.
 
nikolas said:
Small update again.. Bike still at the dealership, they spotted signs of moisture in one of bike's ECUs so they are waiting feedback whether to replace the specific part, and if any actions need to be taken regarding the prevention of moistrure (re)appearing on the ECU.
Click to expand...
Sorry for your continued problem. Riding “season” is probably year-round for you, right?
 
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