Hi gang

I have a 2014 s max 2.0l diesel powershift which intermittently shows "engine service now" and sometimes refuses to start unless I lock the car and start again.

I have a cheap ebay odb reader and the only fault codes are p269f exhaust after treatment glow plug open circuit.

Took it to a garage they couldn't see any codes but we decided to replace the dpf injector and do a dpf clean as it was pretty blocked.

All was fine for 2 days,no codes on my reader ,but went to start it today and came up with the "engine service now " fault and wouldn't start untill i locked and unlocked it

Any ideas what i can do next ? Could it be the relay ? It's such an intermittent fault and the car drives fine ,but unless the fault is present my mechanic cant see any codes

Any help appreciated

Welcome!
BUT, here we go again...
Need to get Ford codes (Forscan and app or lead with laptop) there are multiple threads listing this which you should be able to find, or ask.
You can then monitor as soon as the fault appears - don't switch off until you have captured the codes (cheap OBD reader may not pick up Ford specific codes)

I don't understand the bit about having to lock car due to complete failure to start - this could be a separate /different/additional problem (more codes/live data needed?)?

If the vaporiser fuse blew then, as said it would likely be vaporiser glow plug (been there, had that but I tested the resistance which, whilst within spec was blowing the fuse and, on specialist advice changed it)
The car then did it's own regen (monitored on Forscan) - no problems since.
SO, if that fault is back, you'll need to monitor DPF pressure differential and find the source of the fault (DPF is usually a victim)
I'll give my usual reference to Jimmy's channel for all things DPF:
https://www.youtube.com/@ORileysAutos/videos