Can this EDIAG YA201 diagnose my engine fault? 

I actually used to design these types of equipment many years ago for a well known brand. Code readers do NOT detect faults no matter how cheap or expensive they are. The cars ECU does all the work and the code reader mearly reads what the ECU tells it. EOBD is a standard that all code readers can use irrespective of price. Of course more expensive readers can access non standard manufacturer specific functions. Your first fault code that failed to be diagnosed was non critical and would have eventually showed up after one or more drive cycles as they try to prevent nusance codes from showing up. The car did detect it but just delayed its progression to OBD memory as per the standard. 😁

Great stuff

Hey Rowan, I find it strange you've went french. I'm old school and my first car was a 92 ford Sierra. I loved the 205 GTi, but when i worked as an apprentice mechanic my boss was always saying if it's not french it's fine. But he always said if it's not jap it's crap. 😂. The majority of the cars needing fixed were always Citroen and Peugeot's. I've never trusted them. But I understand your want to go back to a simpler time. I'd love to go back to my Mazda 323f if they weren't so rust ridden.