As of 2015, the Sears Parts Direct and Appliance Parts Pros websites offer error codes for Whirlpool Duet dryers. Of the two, Sears Parts Direct has the most extensive list.
Appliance Parts Pros lists three error codes. PF stands for power failure, which is caused by a power failure during a cycle. E1 signals thermistor open, and E2 signals thermistor shorted. The site provides a link to a replacement thermistor if the owner determines his is defective.
Sears Parts Direct lists 14 error codes, including power failure. The site also includes troubleshooting information and possible repair parts for each code.