2001 525i wagon - Alarm went off, now won't start

[blackti]

My 2001 525i wagon won't start. This morning, I hit the unlock button on my key, and the alarm went off. The buttons on the key wouldn't turn it off or open the doors, so I had to manually unlock the driver's door to get the alarm off.

Now the car won't start, and nothing electronic works. When I try to start the car, the battery icon on the dash glows dimly, the oil light is lit, and the airbag light is lit. No other dash lights come on. The light near the "P" on the gear selector that is usually always lit is in a dim, fast flicker. When I try to start it, there is no ticking from the starter, no electrical hum, and no sound from anywhere else. I've tried both keys in case it's a key/EWS issue but got the same result.

I checked for blown fuses, checked the battery post connections, and everything seems to be fine. I have not set the immobiliser code, but the OBC buttons don't respond anyway. There were no symptoms of a weak battery before this. The car has sat in a warm garage for the past five days, so an interior light or something could have had time to drain the battery.

Hoping it was just the battery, I tried to jump it, but that made no difference. I get the same few dash lights and no starter ticking. In my experience jumping other cars, I usually get dash lights and other power right away, even if I don't instantly get enough power to turn the engine over. It's an automatic, so I can't push start it.

I wanted to see if anyone had any ideas for troubleshooting before I either check/replace the battery or have the car towed to my local independent shop. I searched, and didn't see anyone else with the same symptoms. Usually, there's some interior power, some ticking...somthing.

Since the jump had no effect, I'm worried that it's not just a dead battery. It's the only car I have at home right now, so taking it to a parts store for testing will be a hassle, especially since I suspect a bigger issue.

Please let me know if you have any ideas. Any help would be appreciated.

[bboh]

Sounds like there might be some sort of cut off switch for the alarm. ??? Maybe a stuck alarm relay prohibiting electrical power??? I have the same car, but I've never set off the alarm to know if the car has that function. I also know absolutely nothing about how the alarm works. I'm not much help since I'm not at home right now. I will take a look at my Bentley Manual tomorrow to see if I can dig anything up for you.

Anyone else have any alarm knowledge??????????

[blackti]

Thanks for the response. I'm also concerned that it could be an alarm issue. That system is pretty much a black hole area for me. In the Bentley (p. 121-3), it says that, "Engine doesn't crank," means "fault in immobilizer system (EWS)." A slow crank is more likely a battery issue. The fact that I seem to have weak interior lights though, leads me to believe that it's not just the immobilizer.

I read in one thread that the alarm will be triggered when the car loses power. When I hit the keyless unlock button, the power draw to the locks could have made the alarm realize there was no power. That could explain why the alarm went off, but it doesn't help with finding the fix.

I'm going to try another jump this morning and then test/replace the battery. If that doesn't work, it's off to my mechanic. Hopefully it's not a EWS-type issue that only the dealer can fix.

Does anyone have any ideas about why the starter isn't even clicking? If the battery is totally dead, would it be unable to activate the starter at all? Would a starter just fail suddenly and then not click, or would it slowly die, still click, but just no longer be able to fully crank?

[Qsilver7]

This time...let the battery charge for a while when you have it hooked up to the car your jumping with.

To me, it sounds like your battery is VERY discharged, which means that trying to jump start the car right away still won't work. If you still can't get it to start after having the two cars hooked together for a while...remove the battery and take it to some place like AutoZone and have them test the battery. If it's a goner...purcahse a Duralast 49DL while you're there (approx $79)...and make sure you get the vent kit that should come free with the battery.

[bboh]

Sounds like you did some Bentley searching too. Did you try another key? The key you used might have gone bad?? I also agree with Qsilver7 on the battery issue. When you hooked up your jumper cables, did you notice any interior lights on or did they get brighter?

[blackti]

Thanks for the advice, guys. I was more patient with the jump and got it to fire up. I drove around for 45 minutes, parked it for a few hours, and it restarted just fine. It was also fine this morning after sitting all night.

I'm inclined to buy a new Duralast as preventative, maintenance since it was fully discharged. I bought the car a year ago and don't know the history of the Exide battery that's in it. Good idea or overkill?

Another possible sympton: After starting it, letting it run, and then listening under the hood this morning, I noticed a very faint fan hum near the driver's side cabin air filter. I didn't have time to see if it stopped when the car went into sleep mode after 15+ minutes. I have never had HVAC problems, so I'm thinking this is just the normal air sampling fan and not a bad FSU. I'll check it tonight and report back.

[blackti]

The plot has thickened since my last post a few weeks ago. The new battery seemed to be fine and tested healthy after a few days. Approximately a week later, it was dead again and wouldn't hold a charge overnight.

My local, independent shop has determined that something is waking up the general control module, but they can't replicate the problem or locate the cause. It is my understanding that they have all the appropriate diagnostic equipment. They aren't getting unusual codes, and the only tangible symptom is that the the alarm goes off periodically.

The car was in a very minor, front end collision six months ago. The front bumper was replaced, but no sheet metal was touched, and nothing mechanical was affected. The body shop screwed something up that caused the fuel filler door fuse to blow (rendering the wagon hatch inoperable). After replacing that fuse, I have had no other problems. We initially thought that the body work may have led to a loose connection, ground, or frayed wire, but they insist that they have spent a lot of time systematically going through everything without any luck.

My shop is taking it to a BMW factory tech in the next few days and hoping for some additional insight. If that doesn't lead to a fix, I'll give the dealer a shot at it.

Any fresh ideas would be appreciated.

[PJB]

Well, I can tell you that my alarm was going off randomly when my OEM battery was failing about a year and half ago. Seeing as how my car is a 2000 and your car is a 2001, and assuming that the Exide battery was in the car when purchased new, it makes sense that it could be on its last legs seven years later, just like mine was. I got the AutoZone Duralast battery, and I would suggest doing the same. Though you patiently charged your battery, an old battery just won't hold that charge as long as a fresh battery will. I would say at the least, you top up your battery (if it's not the maintenance-free type) with distilled water. Either that or get a new battery. I think it's due time anyway, and if may just cure your problems. At a little less than $100 for something your car can benefit from anyway, I would suggest that it's worth a shot. The ONLY times that I've ever had electrical problems with the car are when my battery was dying.

[flipppalot]

I had a similar prob all the indy shops I went to couldn't tell me sh!!. Finally went 2 stealership they said the violtage was dropping in between the cross member and some sh!!. They told its the earthcable .4 hours of labor later battery never died. Ask jackeatsemoskids about this.he's a bimmer tech

[waapples]

This sounds very similar to what happened to my 528i after a long vacation.
Of course, I wasn't prepared for the battery tender back then and "even locked my car" in the garage while we were gone. My folks stopped by pretty much everyday but I didn't hand them over my car key since they don't know how to drive manual tranny.

Upon returning back from the vacation, I stepped into the garage and un-alarmed/open the car, the alarm went off, almost got a heart attack from the sound, since I didn't expect it at all.

Jump started it using my father's car, no luck, the battery didn't have enough juice left in there.

All resolved after replacing the battery. That was all.

[blackti]

Thanks guys. I replaced the battery a few weeks ago, but the problem returned. I'm going to give my shop one more chance, then it's off to the dealer.

[00BMW540i6]

FSU? It's a long shot, but ya never know.

[FP5241]

Not as long a shot as one might think...
My alarm used to trip alot too.... then my battery started dyin out on me... sure enuff.. my FSU went south and was suckin all my juice. (eww)

The alarm goin off by itself IS a sign of a bad/low battery... Try replacing a $70.00 FSU before you pay to haul it to a shop.

Good luck.

[blackti]

Now the shop is telling me its the FSU. With the aid of a new diagnostics equipment, they were able to observe and isolate the draw. They initially thought the FSU was an unlikely cause, because the fan was functioning normally. Hopefully, this solves the problem.

[rdoubled]

My alarm is randomly going off also, FSU? Fuel Sending Unit??