2004 X5 4.4L w/ 85k miles

My SES light came on about a week ago and I pulled code P1434. Most recommendations suggest starting with re-seating the gas cap and or replacing it. Seems like a longshot, but it's a cheap part. My new gas cap came in yesterday and I plan to install it today. Two questions:

1. Bit of a newb question but should I clear the code after putting the new cap on or will the code clear itself if that was the cause?

2. Has anyone else had this particular error and had to replace parts beyond the cap? Just curious what to investigate next if needed. I've seen everything from the DMTL pump to the MAF referenced but wasn't sure if there was a common related failure more unique to the e53

Thanks in advance