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HELP !!! 03 745Li won't start

77K views 163 replies 45 participants last post by  Jackjones 
#1 ·
my 745Li all the sudden won't start, :cry: it was trying to crank, but then it got weaker and weaker, and after a few more try on press the start button, it totally gone dead now. I though the issue may be the battery and have AAA come and charge the battery directly at the trunk but no luck :thumbdwn:. Any other suggestion on troubleshoot before I point the problem to the starter ? My car do have problem with oil leak, not sure if the oil got to the starter !!! : (
 
#67 ·
The power module is in the trunk on the right side behind the door in trunk. Have someone push the button while you see if the sound is from there. It's purpose is to shut off things if you are getting too much voltage. Undervoltage effects it too. I have a power module and a integrated supply module for sale on eBay right now for cheap. Let me know if you need them. The power module new is $486.00. It can easily be swapped out yourself but it does need to be coded to you car. Here are some pics.
 

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#71 ·
On my 550 when the alt was giving me problems every light came on the idrive this did nothing at all just went out and no lights at all but will try to play around with it

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You didn't get it: there is a difference between problematic and stuck alt.
Simply remove the belts and try to start it if you haven't burned the starter yet, try to spin the engine with the wrench
 
#72 ·
Alternator would cause fault codes and warnings like transmission failsafe. The starter is underneath the car and under the reinforcement plate. The battery and power module is where you say you hear the sound. The integrated power supply is underneath the passenger side cabin filter.
 
#76 ·
We toke belt off turn engine it turns left and right with no problem. We then tryed turning alt pulley not spinning at all locked in place. We then checked starter its getting 11 volts try starting with belts off still nothing.

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Bad Alternator. If you decide to rebuild it I have a brand new voltage regulator for the original Valeo unit. You would just need brushes then and a rebuild place to do it.
 
#79 ·
Heres the deal. We changed the alternator Did not start so we changed the starter car is turning over but still will not start. New alternator and starter but still wont turn over. Wants to start but not. Any ideas of what it could be now.


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#90 ·
While lastest update. Car still not starting after trying all advace. Car is currently at dealer to get to the root of the problem. I'll keep all postes on results as soon as they call me today. Worse or all its my bday and I have to real with this.

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#94 ·
I have an 07' 750i Sport and the exact same thing happened to me this morning. The car started fine. I stopped at Dunkin Donuts to get a coffee and when I came out - it wouldn't start back up. All the lights were on, nav, everything. I called AAA and after about 25min of waiting, I tried to start it again and it started.

What I did notice prior to it starting, it was saying that the transmission would be in "safe mode" or something like that. But like I said, it did end up starting and running fine.

So - what would be a culprit of this?

Thanks in advance!
 
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