Car won't start

Got back from a 3 day trip and I go to start my 01 525i and it won't start. I thought it was just gas because I was a little low before I left. But when I filled it with a couple gallons, it still wouldn't start. At 1st it didnt make a sound. Electronics came on fine, but nothing in the engine department. Then after about the 3rd time, I heard a slight "moaning sound", and electronics lights were dim. I'm thinking it could be the battery but I'm not sure. Any ideas?

Update: I just bought a battery from autozone. After checking out, he told me I would have to take it to the dealer to get it "flashed" and it will probably cost an additional $100-$160. Is this true?

Battery, jump start it.

You probably have battery drain, number 1 cause is the FSU. If you search on here you'll find a lot, inc a DIY on how to replace it and info on how to diagnose battery drains.

If you've not noticed erratic blower performance, or none at all, probably not the FSU. Another failure symptom is inability to control the blower speed.

Battery s/b at 12.5+ after setting overnight. With engine running, s/b 13.5+. Measure and report back.

Originally Posted by Sequence

Got back from a 3 day trip and I go to start my 01 525i and it won't start. I thought it was just gas because I was a little low before I left. But when I filled it with a couple gallons, it still wouldn't start. At 1st it didnt make a sound. Electronics came on fine, but nothing in the engine department. Then after about the 3rd time, I heard a slight "moaning sound", and electronics lights were dim. I'm thinking it could be the battery but I'm not sure. Any ideas?

Update: I just bought a battery from autozone. After checking out, he told me I would have to take it to the dealer to get it "flashed" and it will probably cost an additional $100-$160. Is this true?

Only f10 newest five.

Great...Just replaced the battery. Problem solved!!! Thanks

I'd strongly recommend you check for a battery drain, put an amp meter between negative on battery of car with car locked, wait 16 minutes for it to go to sleep and check the current is ~40mA. (There is good guide on here)

I had a leak on my car, put new battery on it not knowing I had a leak. Everything was fine for month or so, until i didn't drive it for a 2/3 days*, then the battery was flat again. Letting the battery go flat isn't good for it, so you damaging your nice new battery if it happens.

Originally Posted by mbell666

I'd strongly recommend you check for a battery drain, put an amp meter between negative on battery of car with car locked, wait 16 minutes for it to go to sleep and check the current is ~40mA. (There is good guide on here)

I had a leak on my car, put new battery on it not knowing I had a leak. Everything was fine for month or so, until i didn't drive it for a 2/3 days*, then the battery was flat again. Letting the battery go flat isn't good for it, so you damaging your nice new battery if it happens.

Did you find out where your leak was coming from?

Yes, it was the AC Control panel that I'd replaced after my original one died. The second hand unit I bought had a fault. Very very unlikely to be the same issue on yours.

It may have just been your battery but for the sake of a few minutes it best to check rather than get stranded somewhere.

Well My LCM is having problems so it could be draining battery slowly. I have a new LCM in hand ready to be installed as soon as I fix the seals on my Sunroof + Windshield.

LCM/LKM needs to be coded to work correctly.

Yeah I've already got a guy who will code it for me. The Tamper dot is "undesirable" in the eyes of many, including myself

You could check at the battery for a leak if you concerned or modify a fuse so you measure a the current following through a circuit and still that in place of the fuse for the LCM/LKM.