HELP!!! CEL came on, Code P21A9

[Hayes21890]

My wife and I recently bought a 2012 X5 35D, about a week and a half ago actually. It has 53k miles on it and is bone stock. We just drove it 1300 miles over the past week to see her family and back and when we were in Michigan, driving through downtown Ann Arbor, the CEL came on. Got it checked out and it was P21A9 and from my understanding with some research, it looks like it is a sensor for the exhaust? Some threads I saw mention something about the gas tank (diesel tank) needs to be replaced. But, I am not sure. Can anyone help me out here? I am frustrated because we bought the car from a BMW dealership in Tennessee and live in NC so taking it back to that dealer is out of the question. Is there a simple fix or anything after-market that will fix it? It does not have any warranty on it nor is it CPO so not concerned about breaking the warranty factor.
Any help is greatly appreciated guys!

Edit: Forgot to mention, the light was on for about 25 miles (parked it over night at her families place) and came back on after about 450 miles of driving. Both times it came on, it happened to be in a big city with traffic. Downtown on both occasions.

[-c-]

Originally Posted by Hayes21890

My wife and I recently bought a 2012 X5 35D, about a week and a half ago actually. It has 53k miles on it and is bone stock. We just drove it 1300 miles over the past week to see her family and back and when we were in Michigan, driving through downtown Ann Arbor, the CEL came on. Got it checked out and it was P21A9 and from my understanding with some research, it looks like it is a sensor for the exhaust? Some threads I saw mention something about the gas tank (diesel tank) needs to be replaced. But, I am not sure. Can anyone help me out here? I am frustrated because we bought the car from a BMW dealership in Tennessee and live in NC so taking it back to that dealer is out of the question. Is there a simple fix or anything after-market that will fix it? It does not have any warranty on it nor is it CPO so not concerned about breaking the warranty factor.
Any help is greatly appreciated guys!

Edit: Forgot to mention, the light was on for about 25 miles (parked it over night at her families place) and came back on after about 450 miles of driving. Both times it came on, it happened to be in a big city with traffic. Downtown on both occasions.

Sometime sensors go bad and need replacing, always go with the cheapest fix first and work your way to the big ticket items unless you know for certain what the issue is. Since I don't have the diesel I can't help but it seems having to change the whole tank seems a bit outrageous.

Good luck!

[Hayes21890]

Originally Posted by -c-

Sometime sensors go bad and need replacing, always go with the cheapest fix first and work your way to the big ticket items unless you know for certain what the issue is. Since I don't have the diesel I can't help but it seems having to change the whole tank seems a bit outrageous.

Good luck!

I agree, it does seem a little wild that the tank would need to be replaced. I did some research but came up empty for the most part. Would love to get some input from others who have experienced the same issue.

Thanks!

[Weebl]

If you get moisture/water in the diesel you can get fungus or some such in it. My 12d had no CEL come on but they spent >$15k trying to fix it.

Looked up your code quick and it looks like it might be the DEF tank, not fuel.
http://www.e90post.com/forums/showthread.php?t=865665

[Hayes21890]

Originally Posted by Weebl

If you get moisture/water in the diesel you can get fungus or some such in it. My 12d had no CEL come on but they spent >$15k trying to fix it.

Looked up your code quick and it looks like it might be the DEF tank, not fuel.
http://www.e90post.com/forums/showthread.php?t=865665

I found that thread too but it does not seem to give a proper fix. Or at least one I want to agree with! Haha! Don't want to come off $1,500+ for a fix. Plus, that thread is almost 3 years old and didn't know if a new fix has since come about.

[Hayes21890]

bump!