2006 e90 won't start

[kjanko]

Hi guys,

I have an e90 from 2006 and I am facing a major issue with it.

This morning the car was fine and I took it for a drive. After parking and letting it stay for an hour, I tried starting it without success. When I presses the start button, the electronics rebooted, I heard noise in the cabin from something - but no engine sound. On second try It worked and I parked it home.

Tonight I had the same issue, but it took me 10 minutes to start it. After that, I drove it for 200km and it seemed fine. I parked, and trief to restart it - no success this time. Took me 20 minutes to get it working again, and after that it started few times consecutively.

I turn it off, wait a couple of minutes thinking the issue is gone and try again - this time the cabin monitors start acting wierd, like the car doesn't have enough electricity. I wasn't able to start it. Soon afterwards the keys stopped working as well - was not able to unlock it nor lock it.

What's causing this? Is it a dead battery?

[sshivaram]

check the battery voltage. Should be around 12 volts. Anything below 11volts is bad. How old is the battery. It usually has date/year of manufacture on it. They last about 6 years.

[kjanko]

It shows 2.76v, it's completely drained though. The thing is, since I drove it for so long it should have charged. Could be the alternator as well...

[sshivaram]

Once voltage falls below 10, battery is dead and has lost capacity to retain charge. I highly doubt its the alternator. A fualty alternator wont let you drive the car for more than 4-5 mins just on battery power.

[kjanko]

Should it jump start if the battery is dead? We tried to start it from a bmw x5 with no success

[Fa20vishal]

Definitely get the battery tested. Similar problem with one of my buddies e90's. Take it one step at a time and dont overthink anything. My bet is the battery. Not enough cranking amps. Especially with cold weather. Idk where you are located though..so..

[sshivaram]

My 2006 325xi was dead and i couldn't jump start with my M5. I took the M5 battery out and plugged it in and it cranked up.

[kjanko]

It was the battery.