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View Full Version : I Almost die! 2DEC Power Management causing voltage spikes



ozan
09-09-2021, 10:11 AM
Thank you in advance to all, and would really appreciate any advise on what I experienced. The car has "02DEC" fault code, which is about car voltage issue.

I have a 2010 BMW E90 with N43 engine, automatic transmission. Today I could have had a very serious accident, but luckily nothing happened. For some reason, the electricity of the car shut down for 4-5 seconds while driving around 50mph, and I even could not turn the hazard lights on. Below I tried to explain the problems I am recently having with my car. I first noticed something was wrong with the car on 17th of July when I did a long journey for a day trip to the Norfolk area from Leicester (120 miles). Because I started to journey in the evening and drove the car in dark for a long time for the first time, I was able to notice the front headlines were flickering, but I did not feel that this could be something that would cause other problems, which I now think is what is happening actually …

The problem does not happen when I first start the car, or if I use it for a short distance. However, after driving the car for a relatively long period (between 30 min-1 hour), after the engine reaches operating temperature, if I slow down or stop in traffic lights, etc., flickering on headlights and interior light starts to happen. When this starts to happen (I believe it’s about car voltage or electricity in the car), if I try to park the car, the steering wheel starts to feel strange (kind of heavy). I believe this is because something in the car uses more energy than it needs, or the alternator fails to regulate voltage level, or there is a wiring/grounding issue, IBS sensor, fuse, relays, etc.

Besides these, once the car starts to show these symptoms if I stop the engine by pressing the engine switch button, the whole electricity cuts off and the key remains locked in the fob. (please see attached link showing this issue). Nothing in the car functions (i.e. radio, headlight, cabin light), and no light on the dashboard. This has happened at least 12-15 times since the 17th of July. Sometimes the electricity comes back if I keep opening and closing the car doors, and sometimes it comes back while doing nothing. However, it takes for the car at least 35second or 5minutes for electricity to come back. Once this happened on the last week of July, I was on holiday in the Cornwall area. The next day, I drive the car to the closest Kwik Fit centre, and had its battery and alternator checked, and the mechanic told me my battery seems to work fine It's really strange because I also know my Vatra battery is only 8 months old and specifications of the battery match my car model.

Before I experienced all these, my High-Pressure Fuel Pump failed (around the 9th of July), and I had to park the car somewhere as I was struggling to accelerate, and the car behaved strangely. After this, my local mechanic suggested purchasing a second-hand HPFP and replaced it as well as spark plugs on the 13th of July. Although I am not sure, I now feel that this failure of my fuel pump may somehow be related to the pre-existing voltage issue on my car, which I did not know at that time.

Finally, today I was driving to a fruit farm with my cousin and her 3-year-old daughter, and I was not very fast. After a cold start, and 3 miles of driving, all of sudden the car lost whole electricity for a moment and I could not even turn on hazard lights. I was so lucky that there was no car behind me, and the electricity came back 3-4 seconds later while I did touch nothing and the car had no engine power I believe. After electricity started to work, I received an error showing that my right beam light was not working anymore, which I think is due to high voltage.

This makes me feel it could cause a serious accident, and we were really lucky today. I started to lose my confidence in my car, and I do not even consider selling the car to someone else in this condition as it could cause fatality.

Here is the link showing the symptoms of electrical issue on the car.

https://www.youtube.com/watch?v=ZPbjUZ_8v7w&ab_channel=ozan