Quote:
Originally Posted by RedCardinal
that doesn't make sense, from a car manufacturer's standpoint. Why have the start light stay on like that - as a warning? most of us don't even realize it stays on. It's like adding insult to injury: your battery is low because you don't drive much, so hey I got an idea, let's help it discharge some more ...
Let me suggest that you have a failing EDC module and it will eventually fail completely, leaving that start light on all the time and causing battery drain and possibly battery damage.
I'm speaking from experience: 2013 E93 M3, had intermittent battery drain problems. Sometimes I'd get the increased battery discharge warning when I started the car; then it would go away and I wouldn't see it for months until it happened again.
Eventually - I'm talking like 2 years later - it failed completely, and I'd get a increased battery discharge warning every time I left the car alone for more than an hour.
I took it to a local mechanic that's well-regarded by local BMW people. He updated the car's software, checked for a parasitic drain and didn't find one, told me to come and get it, charged me >$600 ('2 hours labor for updating the software' are you kidding me). When I started the car it gave me the warning. However, just starting the car for those of us in this situation clears the error, as you can read about in the threads: That's one reason dealers have so much trouble recreating the problem. My mechanic went as far as to wonder out loud about it, saying 'huh, no one would make THAT up," implying that he thought I was making it up.
However I will say this: his determination that there wasn't a parasitic drain meant I could stop looking for one. And then I found the threads about the start button and sure enough, it stayed lit. All day and night.
Bought a new EDC, installed it myself, bam. no more problem. edit, my bad, I bought a USED EDC on ebay for like $100 - it was new to me.
(just fyi, if you need an EDC module, it does not have to be from the same car as yours as long as it's the same part - but in the case of a different type of car you may be required to re-code the module: I don't know as I bought one from a 2011 e92 M3 and just copied my EDC's coding on to it.)
This was only a few days ago, so we'll see if it solved the problem long-term (after all it had always been intermittent until like a month ago - at which point I took to disconnecting the negative battery terminal every time I parked the car at home).
So if your problem occurs again I'd def recommend swapping out the EDC.
Oh and by the way, afaik my EDC also 'worked' as it should - in other words the normal function of the electronic dampening worked. But for some reason, the start light is wired in to this thing....
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The Start Stop button is not connected to the EDC module in any way. The start stop button is only connected to the CAS module via a ribbon cable.
Though the EDC module staying awake will cause the start/stop button to remain illuminated, and replacing the EDC module may fix some cars, it is by no means the only reason that button stays on.
IN the OP's instance, the overly discharged battery was keeping the IBS active, which wasn't allowing terminal 30G to deactivate, keeping things like the Comfort access module, CAS, Footwell module etc on, keeping the button illuminated. If that buttons led doesn't turn off, it's because the CAS module is staying on. If the battery is drained below 60% SOC consistently, the CAS module will remain on. why is it programmed that way? No clue. But if it remains on, terminal 30G and 30F will remain active and some modules will stay on, and the button will remain illuminated.
To diagnose, run a power management test, followed by a test plan on anything PTCAN, or FCAN related. The faulty module will have something like "terminal 30G Circuit violation" or a similar fault if its indeed staying on after it's suppose to shut off.