BMW X3 Power Loss & CEL: Bad NOx Catalyst Warning

I had nearly identical symptoms with my 2020 BMW X5 last year. The exhaust leak was causing the power loss and triggering the check engine light. After inspection, turned out the exhaust manifold gasket had completely failed, and there were cracks in the manifold itself. The mechanic found the leak was happening right before the catalytic converter. This was actually pretty serious since the exhaust gases were escaping before reaching the emissions control systems. The manifold and gasket needed replacement, plus they had to check the catalyst for damage from the excess heat. My car runs much better now, full power restored and passed emissions with no issues. Don't wait too long to get it checked. These leaks can damage other components if left unattended. Make sure to ask them to pressure test the entire exhaust system to find all potential leak points.

Hey, thanks for sharing your experience! That sounds exactly like what I'm going through right now. I'm just curious, do you remember roughly how much you ended up paying for the whole repair job? Also, has everything been running smoothly since then, or have you noticed any other issues pop up? I'm trying to get an idea of what I might be looking at cost-wise and whether this fixes the problem for good. Thanks!

Hey! Glad I could help. I actually just got everything sorted last month. The total damage was 265 € to fix the exhaust leak, which wasn't as bad as I initially feared. The mechanic also discovered and fixed the NOx storage catalyst aging issue while they were at it, which was a bonus. Since the repair, my X5 has been running like a dream, no more power loss, check engine light is gone, and it's purring like a kitten. Haven't had a single problem since. The emissions are perfect now too, so that's one less thing to worry about. Just make sure you get a thorough diagnosis, my previous mechanic missed the NOx catalyst problem completely, which could have caused more issues down the line. But honestly, once you get it fixed properly, you should be good to go. Mine feels like a completely different car now!

Hey! Thanks for checking back. Just wanted to give you an update since I got my car fixed. You won't believe this, but it turned out to be such a relief! I took it to a new mechanic I found through a. They did a complete diagnostic and found both the exhaust leak and a worn-out catalytic converter. The whole thing set me back about €1,200, but honestly, it was worth every penny. They replaced both parts, and the difference is like night and day. My BMW's running super smooth now, no more check engine light, got all its power back, and the best part? It passed the emissions test with flying colors last week. I'm just glad I didn't wait any longer to get it fixed. The mechanic mentioned I could've ended up with more serious problems if I'd kept driving it in that condition. Haven't had a single issue since the repair, and it's been about three weeks now. The engine sounds so much better too, no more weird noises when I accelerate! Thanks again for your help earlier. Really helped me understand what I was dealing with before heading to the shop.