[GrabEmByTheBimmer]

Just returned from weeklong trip. Parked in covered airport parking. Turn f30 335i on on and I get hood open, drivetrain warning (do not turn off engine or it might not re start) and some others. The gauges don’t even light up move. HUD shows no speed when driving. What gives? Only thing I did recently was install a renline phone mount in the dash. Had no issues after it. Had to disconnect and reconnect battery for it but I did it properly.

Any ideas? Turning off and on again did not fix. Shit!

[toxik]

maybe a mouse/rat got in and chewed up some wires while it was parked. have you looked under the hood to see if anything looks strange?

[ashkanvafaee2]

Low battery?

[Billfitz]

Originally Posted by ashkanvafaee2

Low battery?

Not likely. Once the car is started the alternator provides all the juice the car needs, even if the battery is disconnected. The hood open warning makes me think that someone jimmied it and did a job on something.

[schernov]

Most likely bad battery. Charge it overnight to make sure it puts out 13.4 at least.

[eluded]

https://youtu.be/md3B3I7Nmvw

[MidtownMike]

You may have boyz n the hood.

Ok, seriously: Billfitz knows a lot about our car electronics, so definitely respect his opinion. It might however be that the alternator was already going bad and not providing enough energy to keep the battery charged, which caused it to go low. I would definitely start with checking both battery and alternator voltage. The symptoms do sound like those seen when the voltage is too low.

[Billfitz]

Yep. Low voltage can cause all sorts of problems, but low voltage doesn't necessarily indicate a bad battery. More often than not it's something else. You don't have to search very far to find posts from those who took the advice to get a new battery and it didn't fix the problem that was causing low voltage.

I once had every warning that the car can show pop up on my dashboard at the same time, including 'Go directly to the dealer, do not pass go, do not collect $200'. It took my code reader thirty seconds to identify the problem as an ABS wheel speed sensor. Speaking of which, that's what the OP needs to do. He can do so himself, or pay a stealership upwards of $100 to do it.

[Wires]

Originally Posted by Billfitz

Not likely. Once the car is started the alternator provides all the juice the car needs, even if the battery is disconnected. The hood open warning makes me think that someone jimmied it and did a job on something.

You sure that's the case? With a generator, yes, alternator needs power to run the windings for back EMF to charge. Unless modern cars are different than yester-year cars...

Battery is also needed to "smooth out" 12V. Works as a giant capacitor for the electrical system.

[Billfitz]

When I worked for Ford we had to take an entire defunct dealer's inventory off his lot. Most of them had batteries that were so dead that they couldn't even be jump started, as they just sucked up the voltage that the donor car was giving them. We didn't have the luxury of being able to wait for a half hour or more for the donor to charge the recipient enough to turn over the starter. But unlike the rest of our office crew I was also a mechanic, so I knew what to do: disconnect the battery negative, jump start the car, then reattach the battery, which the car would then charge. It worked a treat.

In the OPs case he wasn't running without the battery in any event. His battery may have been low enough after sitting for a week to cause the power management system to divert power away from non-critical systems, and if it was that low it would take a while for the alternator to charge the battery sufficiently for them to come back on line. But sitting for a week in and of itself usually wouldn't cause that much drain on the battery. A parasitic current drain would. If that's what happened a new battery won't fix it. That parasite would kill the new battery too.

[HighlandPete]

Originally Posted by Wires

You sure that's the case? With a generator, yes, alternator needs power to run the windings for back EMF to charge. Unless modern cars are different than yester-year cars...

Battery is also needed to "smooth out" 12V. Works as a giant capacitor for the electrical system.

The fact the engine started and there is no mention by the OP of a low or discharge battery warning, does gives clues something else is wrong.

Simple voltage test on the battery and with engine running will give an idea of charging being okay.

Agree that a low battery can cause all sorts of issues, but also agree many battery replacements are not really required. Seen so many users over the years get told an electrical issue is the battery, to still have the initial problem back either immediately, or after a few days driving as the battery loses its charge.

[GrabEmByTheBimmer]

The warnings went away after about 35 min of driving. Gauges lit back up. I hope it was due to an older battery sitting unused in the cold for a week.

But there’s a check engine light, which displays the following 11 codes on the dashboard DTC section:

E12C01
E12C03
E11450
E11458
E11460
E1145C
E11480
E11420
B7F668
E12C20
E11465


Shit!

[Billfitz]

Clear them, then see if any come back. If they do look them up here: https://bmwfault.codes/