Sunny Diesel Preheating Issue

I had a similar problem with my Nissan Sunny. Is the engine preheat constantly running? It sounds like the preheating unit could be faulty, but did you check the fuses and relays first? It's worth a shot before digging deeper.

Yeah, the engine preheat seems to be running all the time. I haven't checked the fuses and relays yet, I'll do that. But if it's not that, could it really be the control unit? How much did the repair cost you?

In my case, it was indeed the preheating control unit. If the fuses and relays are fine, I'd say it's highly likely. I ended up taking it to a workshop, and they confirmed it. I know it's frustrating, but car electronics can be tricky. I'd recommend doing the same to avoid further damage to your engine.

Thanks for the advice! I checked the fuses and relays, and they seemed fine. So, I took it to a workshop and they confirmed it was the preheating control unit. Cost me 95€, but at least it's fixed! I appreciate the help.