Dacia Logan Diesel Issues: Persistent Pre-Glow Light, Black Smoke, Start-up Troubles, and DPF Regeneration Failure

Hey there, I feel your struggle. I own a 2018 Dacia Duster, and I had a very similar issue not too long ago, just a few ticks shy of your mileage. Heck, I dealt with the hard starts, shaking, even the persistently lit pre-glow light, which can be quite unsettling. Now about your suspicion on the glow control unit, you could be onto something. Remember, the glow control unit regulates the glow plug system which is vital for diesel engines, particularly, during cold starts and idling. If this unit fails, your glow plug also fails to heat up, leading to your observed symptoms. In my case, the culprit was the wiring harness from the glow control unit to the digital diesel electronics, which tuned out to be defective. It seems that this harness acted like a cranky bug, not allowing the signals to transmit properly between the glow control unit and digital diesel electronics. I'd recommend getting the wiring checked out. You should mention the symptoms, your suspicions and my experience to your mechanic. And remember, no need to feel anxious, it's a pretty common issue with diesels. It is a serious affair, but nothing to lose your night's sleep over. Good luck!

Hey, truly appreciate your response. It's good to know I'm not alone in this boat. The glow control unit and faulty wiring harness sound like a plausible cause looking at the symptoms. Your experience with your Duster might just save me a lot of trial and error. Now, I hate to be a bother, but do you recollect how much shelling out you had to do to fix that problem of yours? Also, have you noticed any lingering issues or anything else popping up since that fix was made? Cheers!

Hey, no bother at all! Happy to help a fellow car enthusiast. The problem with the wiring harness set me back a cool 155€. A bit of a pinch to the wallet, for sure, but it was well worth it to have smooth ride again. Ever since the mechanic sorted out the glow control unit defect, my Duster's been running like a dream, no more shaking or stubborn glow lights. So far, no new issues have popped up, fingers crossed it stays that way! Hope your Logan gets back on track soon, too. Safe driving!

Thanks a ton! Your advice has been really insightful. I'll definitely get that wiring harness checked and let's hope the bill won't burn a hole in my pocket. Can't wait to get my Logan running smoothly again. Fingers crossed I won't be dealing with new issues post this fix. And best of luck to you too with your Duster, let it keep on rolling without any problems. Ride safe!