BMW X1 Cold Start Issues: Rough Idle and High Fuel Usage

Hey there! I had a similar issue with my 2015 BMW X3 28i last winter. The symptoms you're describing sound exactly like what I experienced, slow warm-up, rough cold running, and increased fuel consumption. Turned out it was indeed the PTC (Electric auxiliary heater). When I took it to the garage, they diagnosed a complete failure of the heater unit. The mechanic showed me that the auxiliary heater wasn't engaging at all during cold starts, which explained why the engine was struggling to reach operating temperature. It was quite a serious issue since it affected both engine performance and cabin heating. The repair involved replacing the entire PTC heater assembly and reprogramming the control module. It took them about half a day to fix. I'd definitely suggest getting this checked soon because running the engine cold for extended periods isn't great for long-term reliability. Since you're not comfortable with your current mechanic, try finding someone who specializes in BMW systems, they'll know exactly what to look for. Hope this helps!

Thanks so much for sharing your experience! That's really helpful as it sounds exactly like what I'm dealing with. Would you mind telling me roughly how much you ended up paying for the repair? Also, just curious, have you had any other issues pop up since they fixed it? I'm trying to get a sense of whether this fix really solved everything or if I should be prepared for any related problems down the line.

Hey again! Just wanted to update you on my PTC heater repair since you asked. The total bill came to 350 € for everything, parts, labor, and programming. I know it's not cheap, but honestly, it was worth every penny. Since getting it fixed, my X3 has been running like a dream, no more cold start issues or excessive fuel consumption. The best part? It's been over a year now, and I haven't had a single related problem pop up. The engine warms up properly, runs smooth from the start, and my fuel economy is back to normal. The repair completely solved all the symptoms I was experiencing. I remember being worried about potential follow-up issues too, but the PTC heater replacement really did fix everything. My mechanic explained that it's actually a pretty straightforward repair once they know what they're dealing with. Just make sure whoever works on yours knows BMWs well, it makes a huge difference. Trust me, once you get it sorted, you'll notice the improvement right away. Let me know how it goes if you decide to get it fixed!

Thanks for all that detailed info! I actually bit the bullet and took my X1 to a different mechanic yesterday. You were spot on about the PTC heater, that's exactly what it was. Got it fixed and wow, what a difference! The engine's now warming up properly, and that rough running is completely gone. Funny thing is, I was so nervous about going to a new mechanic after my last experience, but this guy really knew his stuff. He walked me through everything, showed me the faulty part, and explained why it was causing all those issues. The bill was pretty similar to what you paid, around 370 €, which wasn't as bad as I'd feared. Took it for a drive this morning and it's like having a different car, smooth from the start and the fuel gauge isn't dropping like a stone anymore. Should've done this weeks ago instead of worrying about it! Really appreciate everyone's help and advice on this. Sometimes you just need that push to get things sorted, you know?