Macan Glow Plug Nightmare: Black Smoke & Starting Issues

Hey there! I had something very similar with my 2018 Cayenne Diesel (also had a Macan before). I've got some experience working on cars, though I'm no expert. The symptoms you're describing sound exactly like what I dealt with. Took it to my regular Porsche workshop last summer, turned out one of the glow plugs was completely shot from wear and tear. Bill came to around 560€ including parts and labor. They had to replace the faulty plug and reset all the system codes. But before I can say it's definitely the same issue, could you share: How many miles/km on your Macan? When did these symptoms first start? Have you scanned for error codes? Just want to make sure we're dealing with the same problem before giving more specific advice!

Thanks for the reply! I've got 135342 KM on the clock. The symptoms started about 2 weeks ago, right after my latest service actually. Haven't scanned it yet, was planning to do that tomorrow at my local shop. Your experience sounds pretty similar to what I'm dealing with. Really hoping it's just the glow plug like in your case and not something more serious with the DPF system. Did you notice any immediate improvement after the repair?

Hey again! Yeah, I remember dealing with this on my Cayenne. After seeing your mileage and timeline, I'm even more convinced it's similar to what I experienced. The timing after your service is interesting, mine actually started acting up after a service too. And yes, the improvement after replacing the faulty glow plug was like night and day! The black smoke disappeared completely, cold starts went back to normal (like 2-3 seconds max), and the DPF started regenerating properly again. Fuel economy improved by about 15-20% too. Just to add to my earlier response, when they diagnosed mine, they found that the damaged glow plug was actually causing the ECU to pump in extra fuel to compensate, hence all the black smoke and poor economy. The DPF issues were basically a knock-on effect from the incomplete combustion. One tip though, make sure they check all the glow plugs while they're at it. Mine had one completely failed, but another was showing signs of wear. Ended up replacing both since they were already in there. Better safe than sorry, right? Let me know what the scan shows tomorrow. If you get any specific codes, I can tell you if they match what I had with mine.

Thanks so much for all the detailed info! That's really reassuring to hear, especially about the immediate improvements you saw. I'll definitely take your advice about getting all the glow plugs checked, makes total sense to do it all at once while they're working on it. The fact that yours also started after a service is a weird coincidence, but at least it points to a similar issue. I'll get those codes scanned tomorrow and let you know what they find. Really appreciate you sharing your experience, it's helped calm my nerves about this whole situation. Fingers crossed it's just the glow plugs and nothing more serious! Thanks again for taking the time to help out a fellow Porsche owner.