Glow plug issue on Mercedes GLE diesel

I've experienced something similar with my GLE. If the preheating lamp remains on, it's highly probable that a glow plug has failed. It's like a lightbulb burning out; one goes and the whole system suffers. Have you noticed any difficulty starting the engine, particularly in cold weather? That's usually a telltale sign.

I haven't had any issues starting it, even when it's cold. That's why I was unsure. Could it still be the glow plug even if the engine starts fine? Were your symptoms exactly the same as mine or were there any other obvious signs? Did you notice any impact on fuel efficiency?

Yes, it is possible. The engine might start fine initially, but the faulty glow plug will eventually lead to issues. In my case, the symptoms were indeed the same: the preheating lamp issue and the stored error. I recommend consulting a workshop to confirm the diagnosis and replace the defective glow plug.

Sounds like it's time to bite the bullet and head to the workshop. The mechanic confirmed it was indeed a glow plug issue and quoted me around 440€ for the repair. Thanks again for sharing your experience!