Service Engine Light On problems of the 2006 Nissan Xterra

Filled up with gas. Drove approx. 5 miles and service engine light came on.

I recently had my recalled ecm relay replaced after it failed, the very next day my service engine light came on. I found a p0430 code saying that the catalyst efficiency was below threshold on bank 2 (failed catalytic converter). I called the dealer to tell them what trouble code I had found and to see if the ecm failure was related. He said he would look into it and call me back. During that time, I did some research and found sites where people had discussed having the same issue. When the dealer called me back I told him what I had found, it was at this time, he told me that it was a common issue & that he would look into trying to get it covered under warranty even though my mileage was just over the 80,000 mile limit. When he called me back, he said that he was getting resistance from his end and that I should contact Nissan directly. I called Nissan, explained my issue, and then waited for them to get back to me with their decision. When they called they said that they would cover $300 of the $1300 cost to replace the catalytic converter. I said, ?only $300?? I feel that Nissan should be covering 100% because it was the failure of the ecm that caused the catalytic converter to fail?. Nissan said, ?our engineers have not determined that the failure of the ecm caused the failure of the catalytic converter, but if at some point they do determine that, we will refund all of your repair costs?. I know the ?cat? failure was directly related to the ecm failure and feel Nissan should cover the entire cost of replacement. I called Nissan back today (12/22/11) to see if I could get them to discuss this issue further & was told that since I did not accept their offer of $300 that the issue had been closed and that I could do nothing more. Nissan will now cover none of the cost to replace the ?cat? because I did not accept their $300 offer. This is wrong!!!.