Hi all, I'm new to this forum but have been on Bimmerfest for a while. I just rebuilt the upper end on an 01 330ci. (Planed head, new head gasket, timeserts in the block, all new hoses, radiator, etc.) bought it with a blown head gasket. The car runs great but illuminuated the MIL lamp and my scanner says P0102 Mass air flow voltage low. I am a little but familiar with hot wire mass air flow sensors. It didn't look dirty but cleaned it with CRC Mass Air flow sensor cleaner. I measured the resistance between pins 1-2, 2-3, and 1-3 and it seems to have very similar resistance to the MAS on my 525. (I can't swap the MAS because the 330 has a larger diameter) The car has a Dinan Intake on it, and the filter was filthy, I cleaned it well, and did not re-oil it before this code set. I can clear the code but it re-sets on the second start up. So, I don't THINK the MAS is bad, the filiments look O.K. the resistance is similar to the on on the 525, and the inside of the boot and MAS were clean. Also, I could kill the engine at idle by choking the intake with my hand, and it held the vacuum for as long as I cared to keep my hand there, over 1 minute, so I don't think there are any leaks bypassing the MAS. Has anyone had similar problems? I don't mind replacing it, but hate to if its not going to solve the problem. I have also read where some people have had to have the computer re-flashed with the Dinan induction. I think it is factory Dinan, is that possible? The studs where standard air box mount have never even had the paint worn off of them. I need to get this fixed, 8 days before the temp tags expire and I need to pass emissions.