vehicle: 2002 prius After some aggressive green light dashes my check engine light (CEL) came on. I ran TIS and found one DTC, P0171, lean fuel mixture, bank 1. Sounds dreadful, but thanks to numerous postings here on PriusChat and elsewhere I decided to clear the code and clean my Mass Air Flow (MAF) meter/sensor. I purchased the recommended CRC MAF spray cleaner. For novices, like me, the MAF is located below the front edge of the air cleaner box, held on with two phillips head screws (PH#2 seems to fit the best.) I detached the MAF, sprayed it, let it dry for an hour. Re-lubed the o-ring on the MAF, put a spot of loctite on the screws, and re-attached it. I've driven a few days and about 30 miles and the CEL hasn't come back on.
Well, that’s great news! It’s so fulfilling when you know you beat the Toyota guys on this one. Thanks for posting this one.
