The only way to tell is to use a DRB-III Scan Tool. It reports which tire is reporting the issue. You can get one of ebay for around $2,500 to $3,000. You can also buy new for $8,900 from Amazon.com.

eBay:
http://search.ebay.com/search/search...trypage=search

Amazon.com:
http://www.amazon.com/DRB-III-Scan-T...8398688&sr=8-2

Also if you order make sure the software version on the tool is at least from 2004.