kevesp

Earlier today I was driving on the freeway, going around 70mph. Suddenly the car jolts, my idrive completely cuts out, air stops, my speedometer suddenly zeros out and stops working, and the lights on my dash light up like a Christmas tree. I freak out and exit at the next exit and stop at a gas station right off the freeway. I shut the car off, wait a little bit, and turn it back on, and the car starts but everything goes off. I've got warning indicators and tones, my idrive is cutting in and out, and my transmission was like it was stuck in high gear it took a lot for it to get the car moving, and it wouldn't shift gears.

Finally my idriv comes back on and I'm finally able to look at the control messages, and I've got a drive control malfunction, flat tire monitor malfunction, abs system malfunction, battery terminal malfunction, and a transmission malfunction. Damn near any malfunction you can think of.

Thankfully I wasn't far from home so I was able to drive it home. Mind you, my speedometer still wasn't working so I had no idea how fast I was going, and my transmission was stuck in 1 gear, which one it was I don't know. The whole time I was listening to the warning tone continuously going off. I had no air my windows wouldn't roll down and my doors wouldn't lock.

I've read around and found others who had this problem and solutions were a failing alternator? Wondering if anyone else has had this issue and what they did to fix it. Please help!

If it helps I have an '05 525i with about 124k. The battery is about a year and a half to 2 years old.

cmyachtie

If you can read any faultcodes, great! If not at least put a voltmeter on the battery or lighter socket and see what voltage yo get with engine running, if 14+ volts alternator is good.
If not get alternator replaced or likely the regulator is toast, which is a cheaper fix then the alternator

johnbennett103

Really sounds like the battery. When you changed it, did it get registered? If not, problems can crop up.

Boost7

it's your alternator or voltage regulator, I had the same problem before too, and when I plugged in a volt meter to the cigarette lighter, I had a better insight as to what was going on.

On start up, it seems normal - 13.7v
after driving for a bit it would spike to 17-18v, this is when the idrive screen will suddenly black out, then all the errors would pop up, SRS, AirBag, Passenger Restraint, Active Steering Fault....everything on the dash lights up...haha

So cmyachtie's suggestion to plug in a volt meter to your cigarette lighter would be the easiest way to start troubleshooting. Even if you try pulling all the error codes, they are actually false, as the system is trying to protect those modules, so they cut off communication when voltage fluctuates.

I replace the alternator and it fixed the issue.

kevesp

Took the car to my local O'Riley auto and the alternator failed the test, along with the starter? Would the starter go bad too if the alternator goes bad? Car starts fine though. The battery also came up with a low charge error, but I'm assuming that's from the apparent bad alternator which isn't charging the battery am I correct?

I had the battery tested by them too and it came back as good. I got the battery registered when I changed it out from a local Indy shop.

Started the car today, and all the original error that came up the day before are gone except for the battery terminal error and the increased emissions?

cmyachtie

Go back to O'Rileys for these last two errors, that should not happen.
EDIT:
My answer based assuming they did fix your charging system!!
Good luck

Boost7

why are you still scanning for error code? fix your charging system first, then diagnose other errors afterwards. if you don't address the charging system, you'll be chasing a lot of false codes and wasting time.

kevesp

Ordered a new alternator online. Should be here in the next 2 days. I'll be removing my old alternator today or tomorrow to get it bench tested to see if it's bad. But I'm curious as to why my starter failed when I got it tested at o'rileys? Should I be concerned about that too?

kevesp

New alternator came in and installed it on my car. Took old alternator to autozone where they bench tested it and it failed. Solves my problem. But when I started the car after installing new alternator, my check engine light was still on. Came up with a P0700 error code. But I'm assuming that code came from the bad alternator?

DanielFD

Possibly. You'll have a bunch of codes in the system. Better get them cleared so that if an issue comes up you won't get 25+ unrelated codes.