[wago2006]

I have a 2006 325xi wagon. Every so often, when the car was parked, the gauge cluster would light up, and the car would shut off, and basically die. Also the key would lock in the dash. Now it is happening more often, usually every day or so. I recently figured out how to get the car going again, but unplugging the battery and 'resetting' the car. However this only lasted so long. Can someone please help me figure this out so I don't get stuck somewhere? I've heard it has something to do with the fuse box.

[gbalthrop]

Originally Posted by wago2006

I have a 2006 325xi wagon. Every so often, when the car was parked, the gauge cluster would light up, and the car would shut off, and basically die. Also the key would lock in the dash.

Best guess from what you describe is a failing Voltage Regulator in the Alternator, which intermittently is causing the Alternator to put out excessive voltage (MORE than 15.0 V). That will cause multiple warning lights to illuminate on the instrument cluster, and play havoc with Electronic Control Units such as the DME (the Engine ECU).

You need to read Fault Codes and Freeze Frame Data saved in the DME. The Freeze Frame Data is particularly necessary, as that will show System Voltage at the time the Fault Code was saved, and if >15.0V, then the voltage regulator is faulty. Also, remove the trim panel on the right-rear of the cargo area, over the battery, and carefully inspect the battery well, and the top of the battery, for any sign of battery acid having been expelled from the battery by over-voltage (which can literally BOIL the acid in the battery). I presume you realize the hazards of battery acid -- do NOT get it on your skin and most importantly, do NOT get it in your EYES.

If you have a DMM (Digital Multimeter) you can measure voltage yourself at the Jumpstart Terminal under the hood. Voltage should be ~ 12.5V with the engine OFF, and in the 13.5V to 14.8V range with the engine running at idle. A Scan Tool (that reads Fault Codes) connected to your OBD II socket can read System Voltage as a Parameter/ Live Data. Another method of reading System Voltage in real time, is to use Menu 9.00 of the "Hidden Menu." Here is a link to how to use Hidden Menu:
http://e90.wikifoundry.com/page/BC+hidden+menus

If you cannot do any other diagnostics with a scan tool, drive with Menu 9.00 displayed on the instrument cluster, showing live System Voltage, and watch for any spikes above 15.0V.

If your System Voltage is >15.0 Volts with the engine running, quit driving the car until you can get the voltage regulator replaced (~ $40 if you DIY), as over-voltage can damage ECU's, damage your battery, and get you stranded somewhere. Here's an example of the part:
https://www.autohausaz.com/pn/BS-12317561939

Please let us know what you find,
George