How do I fix obd code p0401

It appears that code is for insufficient EGR flow.

Some solutions are

• Use a vacuum pump and observe if it opens. If it doesn’t, the valve may need to be cleaned or replaced.
  • Clean or Replace the EGR valve.
• Check the voltage at the DPFE, compare to specified values (refer to a manual for your specific model)
  • Replace the DPFE sensor (with a good quality / OEM one)
• Inspect all hoses and tubes connected to the EGR system for any blockages or leaks.
  • Clean or replace hoses as needed.

EDIT:

It appears you want to know how to replace the EGR valve Egr valve replacement escape