Hey wanted to kick up this old thread as I'm having the same issues. P2247 code and SH-AWD. The SH-AWD doesn't really seem to happen anymore but the P2247 code does. It has gone off at times but will always come back on. Looks like I can get a replacement O2 sensor for around $135 at auto zone. Don't want to spend a ton of money taking this into the shop if I don't have too as it's 10 years old (2008) and I don't want to drop a ton of cash if I don't have too. Currently have 107k on it. Any additional thoughts? Is it worth it for me to get the O2 sensor and replace? Further up in the thread someone mentioned the CC warranty extended to 120k miles and since I'm well under 120k that's good. Would an ODBC device tell me exactly what the problem is??