Most of you know the situation. For one reason or the other, you end up with the dreaded RNOD (Red Nose Of Death) and the dash indicates “Battery Charging Impossible”. Worst case that can leave you stranded, and best case you end up with a disabled cruise control / speed limiter and a that blinding orange light in your face. In most cases this is caused by a grounding fault, and these are often edge cases. The natural response is to simply try again and sometimes this works, but very often it doesn’t.
Unfortunately, the CC/SL will only return after a successful charge, however short. There is not much we can do there (maybe reset the BCB or LBC through CanZE, I never tried).
There are two things that you really need to know, however strange they might sound.
First, remove the charger cable, lock up the car and wait until the car completely powers down. You can sit in the car if you want. Pay attention to the power down sequence. After about 3 minutes, you will hear a soft click and the little LED in the lock button on the top side of the R-Link will go off, as will the auxiliary power. Then, after about another minute or two, you will hear a second, soft relay click. Then, wait another minute. Then CANbus will go to sleep, but there is no indication for that, just wait out that minute. Don’t touch a thing during this wait. Of course you can simply walk away and time a minimum of 6 minutes, but the key is: no cable, everything locked. After this, the computers, and possibly a few big capacitors in the BCB will be in a cleaner state and charging will often be possible. If there is no real grounding problem, you should be able to start the charger normally. I should stress that simply driving to another charger and not going through this “rain dance” usually does not solve the problem.
Second, in some rare edge cases after above procedure, everything will seem to be fine, no errors, but still, the charging process itself will just not start. In the rare cases I had this, I had walked away and retried without opening up the car. Just opened it’s nose, connected the cable, activated the charger. If this happens, unlock the doors. This will wake up all computers, the dash, etc, and that usually makes it realize that indeed it should be charging. The reassuring “clunk” from the charger and the “click – wheeeeeee” noises from under the bonnet will hopefully make you breathe again.
Another problem might be that by accident a scheduled charge is set. So, if the car refuses to charge, look for that little clock icon in the top row of the dash display.
Finally, as was mentioned in one of the comments, a long press on the start button may help, but I cannot confirm this.