BMW M3 Trans Warning: Bad Pressure Sensor Issue?

Hey there! I had a somewhat similar issue with my 2011 BMW M5 last year (also owned a 335i before). I have some experience working on cars, mainly basic maintenance stuff. When my transmission started acting up with similar symptoms, warning lights, rough shifts, and that nasty grinding, I initially thought it was a sensor too. Took it to my regular workshop, and turns out the gearbox oil level was way too low, causing all those symptoms. The fix, including diagnosis, new oil, and labor, set me back 365 Euro. The whole thing took about half a day to fix, and it's been running smooth since then. But hey, could be different in your case, these transmissions are complex beasts. Mind sharing more details about when these symptoms started? Like, did it happen suddenly or gradually? Also, when was your last transmission service? This could help pinpoint if we're dealing with the same issue.

Hey, thanks for sharing your experience! Mine's at 198034 KM and had its last service three months ago. In my case, the symptoms came on pretty suddenly, was driving normally one day, and boom, warning lights and rough shifting. I was actually thinking it might be oil-related too, but since the service was so recent, I'm leaning more towards that pressure sensor being the culprit. Honestly, your experience with the oil level issue has me wondering though. Might be worth checking that first before jumping to conclusions about the sensor. Seems like a simpler fix if that turns out to be the case. Did you notice any leaks when you had your oil level problem?

Hey again! Yeah, after reading about your recent service, your case does sound different from what I experienced with my M5. When I had my oil level issue, I actually found small oil spots where I usually park, should've paid attention to those earlier! But since yours was just serviced, I'm starting to think my first guess about the sensor might've been off. Actually, since we last chatted, I remembered something else, I had a pressure sensor go bad on my old 335i, and the symptoms were pretty much identical to what you're describing. Sudden onset, right after a service, same warning lights and everything. That time, the sensor replacement cost me around 500 Euro, but at least it fixed the problem completely. You know what's interesting? Both times (with the oil level and later with the sensor), the symptoms seemed really similar at first. I guess that's why these transmission issues can be so tricky to diagnose without proper testing. If you're still having doubts, maybe get a second opinion before replacing any parts? These modern BMWs can be really sensitive with their transmissions, and throwing parts at the problem isn't always the best approach. Just curious, has your mechanic run a full diagnostic scan yet? That would probably give you a clearer picture of what's actually going on.

Thanks for the additional insight, especially about your 335i experience. That's really helpful since it matches my situation more closely. You're right about getting a proper diagnosis first. My regular mechanic did run a preliminary scan, but I'm planning to take it to a BMW specialist tomorrow for a more thorough diagnostic. Don't want to waste money replacing parts unnecessarily. Checked for leaks after your last message and couldn't find any spots where I park, which makes me even more convinced it's probably that sensor. The 500 euro cost you mentioned sounds reasonable, was worried it might be way more expensive. Just hoping they can get it done quickly since I need the car for work. Really appreciate you taking the time to share both experiences. It's given me a much better idea of what to expect and what to check for. Will definitely update once I get the actual diagnosis!