Electronic Problems on Initial Engine Startup
 

I have electronic problem that is mysterious to me. On initial startup, the car will start just fine. But after about 1 minute or so, I get transmission fault, dynamic drive, FTM error, alternator malfunction, ABS, Control Systems, and a few other miscellaneous malfunction messages. The radio cuts in and out, and the idling engine bounces slightly during these symptoms. The temperature outside can range between 41F to 77F. It does not matter though the warmer the outside temperature, the fewer the malfunction messages on idrive. The battery is only 1 month old.

One morning, I decided to check the battery first. I took a voltmeter and check the voltage at the battery. It read 12.64v. Then I started the engine. Same symptoms as in the first paragraph. I drove it around for less than 1 mile with speeds less than 30 mph. I parked and turned of the engine. About 20 seconds later, I turn on the engine, and for the rest of the day, the car starts, stops, and runs like a champ.

This problem occurs every morning. Turn on the engine, experience several malfunction errors, drive for less than a mile, turn off the car, turn the car back on, and everything is running good with no error message. Today, when I left work, the error came on again.

What could be issue?

When my car threw a whole bunch of fault codes and had transmission faults randomly, it was the DME.. I had it replaced for around 400 and never happened again. Hard to say though..

Is that the ECU? Do you know why it would be fine after the second restart, but always when the car sits long enough that it goes to sleep, the first restart almost always throw all kinds of malfunction codes?

I would get a voltage meter to test while driving ( $15 or less at walmart).12.5-12.6V is normal before startup. 14.2V to 14.6V is normal while operating. It could be a couple of thing but test your voltage at the battery and alternator. Could be battery (not registered), voltage regulator bad/connection or DME. How many miles do you have. Do you have INPA to read codes?

+1 on voltage regulation. This is a sure sign its got to do with that. Not sure yet how BMW manages things, but in a merc the voltage regulator is on the alternator in the BMW i think the Battery managment or DME is shot or the battery isnt registered. Id start by making sure the battery is registered since its just one month old.

Battery is registered. I think the voltage regulator is on the alternator too. If that is the case, I spend $900 to repair the alternator seal. I should have just replaced the alternator.

Yes the voltage regulator is on the alternator. Two ways you can fix if it is the regulator. Either replace the regulator of alternator your choice.