Engine fault

Hi there. 

 2012 Octavia 1.6tdi

2 days ago, my engine light came on, preheat light was flashing, limp mode. Same symptoms as when the injectors needed replacing.

Plugged the scanner in and got P229b, which according to Google is a fuel pressure issue.

Is there a way to work out which part of the system is the issue? Pump, regulator or, god forbid, injectors?

Cheers