Black smoke, difficult start and DPF problems with the 2010 Citroen Nemo

Hey, that does indeed sound like the control unit. I had similar symptoms on my 2007 Citroen Berlingo diesel last time. It was definitely a serious matter. The ECU had indeed failed, just like on your car, my guess. The symptoms were almost identical, including the shuddering idle and starting problems in the cold. The solution in my case was to change the ECU. In the end, I went to a small garage in my area that was recommended to me by a work colleague and they did a decent job. Hope this helps you!

(Translated from German)

Hi, thanks for your reply! It really sounds like it's going in the same direction. Same problem, same symptoms. It's a good thing I asked. Would you happen to remember how much you paid for the repair to replace the control unit? And were there any other problems with the car afterwards or was everything tiptop again? Have a great weekend!

(Translated from German)

Moin moin! Yes, the symptoms sound pretty similar. In the end, it cost me €1000 to replace and repair the glow control unit. But I can tell you, it was worth it! Since the visit to the workshop, the defect in the glow control unit has been rectified and the car is running like a dream again. No further problems since then. Everything is tip-top again, no shaky idling or starting problems in the cold and the preglow light no longer stays on. Hope that helps you. And thanks, have a great weekend too!

(Translated from German)

Hey, thanks for the info! That sounds like quite an investment, but if the car runs smoothly again afterwards, it's probably worth it. Good to know that the garage you trusted did a good job. I think I'll start looking for a reliable one near me. Thanks for your help and feedback! Have a great weekend too!

(Translated from German)