Focus MkII 1.6 TDCi 2007 reg

EGR fault caused the car to get into limp mode. Tried the intake cleaner with EGR being removed and manually cleaned, but that didn't help. Following ECU reset, the limp mode would come back a few minutes later.

Being absolutely assured that this was caused by an EGR valve fault, I had the entire EGR valve assembly replaced with a brand new one. Since Ford OEM was out of stock decided to buy a new one from TPUK.

Unfortunately, just 1 day after the EGR replacement, limp mode kicked-in again. As per the service station the following codes are active:
- P0490 EGR control permanent
- 042F1 unknown fault code

I am totally in the dark and the service station gave up. Taking the risk to order another EGR valve (Ford OEM) would be a disaster. So far the testing/cleaning/replacement cost more than £500. I also have my doubts whether the EGR valve is to blame.

Any ideas how to do a proper troubleshooting? EGR delete and remapping is an option as well, even though I couldn't find any info on the web that such a thing has been done on the MkII Focus.