Peugeot 207 preheating light and black smoke

Sounds familiar. I've got a 207 as well. Had something similar happen a while back. Was the smoke black or more of a greyish color?

Good question! It's definitely black smoke. Did you get the same lights on the dash?

Yeah, black smoke and those exact same lights. Preheating lamp and check engine light. It ended up being the preheating control unit like you suspected. I'd get it checked out properly at a workshop though; probably an electrical fault.

That's what I was afraid of. I took it to a garage – spot on, defective preheating control unit, cable was damaged. It cost me 95€. All sorted now, thanks for the help!