Excessive regenerations

[Colter]

Please don't just blindly swap sensors, its too expensive to just guess.

The probability that your actual cooler is leaking is much higher then a boot, you can make a rough
tester from PVC although an actual test tool kit will be the same price as one or two sensors.

You can use Insite to check fuel rail leakage, this may fail even without a 0559 code active/inactive but the code will have your fuel system troubleshooting. Even if your out of spec I would still put more weight on air or lack thereof being a more prevalent issue.