I have a 2005 GMC Yukon that hasn't been running just right. It's not bad, just not right. I ran a diagnotic on it & I got a DTC, B-0229. I can't find what that indicates. I'm thinking plugged up Cat comverter, but I really don't feel like tearing the exhaust apart to verify. if the DTC will point out the problem. I'm looking for someone who knows anything about DTCs. I contacted the service dept at the dealer, but they wouldn't devulge any info. They want me to bring it in.