p0401. Fault code. Have had the valve cleaned but fault came back need advice? on 2003 Honda Civic

Hi I had the valve cleaned but the fault has come back as soon as i left the garage. I need a low cost option on what to do next. Do I replace the valve?. The car does make a pinning noise and is slightly rough on idle. This fault came after funning out of oil :( help

Asked by for the 2003 Honda Civic
poss carbon build up in passages or bad valve
Thanks for reply I've replaced the valve with a second hand part. It seems withe the garage did not clean the valve or I have serious engine problems. As I don't think it would take one week for so much carbon to build up the the entrance hole to be almost blocked.
2 more answers , 1 more comment
Are you getting vacuum to the valve? Carbon build up in the ports is a problem.
Can I check this myself? As I live close to only one garage and they are charging me and not fixing the problem. Carbon build up in the ports? Is this on the valve? I've ordered a second hand valve.
Cleaning the EGR port passages will be required. Also inspecting the operating and resting voltage readings for the EGR valve will help diagnose the P0401 code.