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Old 11-08-2012, 05:01 PM   #10
jfoj
Registered User
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 9,609
My Ride: '06 330CiC, '03 M5
Strange faults could be stalling, erroneous trouble codes, lots of lights on the dashboard and so on.

Many times what happens is the modules have a hard time communicating over the databus when Voltages get below a tolerable threshold for the modules.

I never would have believed it until I knowingly took my E46 on a trip when it seemed to have a difficult time starting. I tossed my jumper box in the trunk and thought maybe the battery was just low for some reason. It was the original battery and only about 3 years old at the time.

Turned out the battery had a bad cell and I ended up running with the jumper box in the trunk connected to the battery for the return trip home.

Out of nowhere the brake light, DSC light, and a few other lights would come on, then turn off after a bit of driving.

Also depending on what tool you are using for reading your codes you need to be careful how you interpret the codes. I know on a few of my cars, I have shadow crank sensor codes all the time. Not sure why, however, I have changed the sensor on my M5 with a new OE sensor and still continue to have crank sensor shadow codes, but no known symptoms. I have discussed this with a few other owners and we have other cars that do the same thing.

Good luck, intermittent faults are a PAIN to deal with. I will take a hard failure almost any day over reoccurring intermittents.
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Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temps, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose fan switch O-ring - BMW #13621743299
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