|
Check Battery
Reviving this a bit as I just went through the 2739 and 27C5 plus an occasional random other code issue. Codes would get set on first drive of the day after sitting for a week, but then I'd clear them and they wouldn't come back, even after sitting all day. Car was getting a little slower to start, and on my E39 540i6, when the battery started going flat the dash would start lighting up and it would start throwing codes. With that in mind, I started looking at the battery. Nocco Genius charger full cycle left it at 12.7V and it dropped to 12.4 overnight. Seemed like a big drop over less than 12 hours with no load. Repeated the next night with similar results. Replaced the battery this morning and all is well again. No codes. All I can figure (though I'm probably wrong) is the secondary air pump is a big load as soon as the car starts and may not have been spinning up soon enough to pass the built in test point. In any event, if you're getting these codes, you might check your battery.
|