Whatchain 5 Report post Posted August 17, 2018 Hi guys, got a 2007 335i that keeps getting both of these codes 2C9C & 2C9E coming up even after i clear it. Shows up every time after a start it up but never seems to affect performance. Noticed the check engine light came up after getting the stock muffler welded back on. Person that did it was certain there is no exhaust leak coming from it. What can i do to check for problem before going down the o2 sensor replacement route. could it be fuse or vacuum leak or...? any ideas? Quote Share this post Link to post Share on other sites
