Ford Focus check engine light

I had a similar issue with my Focus. Check the throttle body, including the air supply hoses and vacuum lines. A vacuum leak there can cause the engine to stall and trigger the check engine light. Did you notice any rough idling?

Rough idling? Not really. But you mentioned vacuum lines - were they visibly damaged on your car, or did you find the leak some other way?

Mine were cracked and brittle, but it was hard to spot at first. Given the age of our cars, it's worth a look. Honestly, though, I'd recommend having a workshop take a look. It's a pain to diagnose properly without the right tools.

Thanks for the insight. Turns out the hose connection was indeed defective. Workshop replaced it and the light is off. Cost me 175€ including diagnostics.