BMW X4 Power Seat Mystery: Help with Electric Controls Needed

Hey there! I have some experience working on cars as a hobby mechanic. Had a similar issue with my 2015 BMW X3. The power seats completely stopped working, and the memory settings weren't responding either. Turned out my battery was seriously discharged and needed replacement. After a full diagnostic at my trusted workshop, they confirmed the battery wasn't holding charge properly anymore, which affected various electrical systems, including the seat controls. Got it replaced for about 290 Euro, and everything went back to normal. Before jumping to conclusions though, could you share if you're experiencing any other electrical issues? Like slow starting, dim lights, or other electrical functions acting up? Also, do you know if your battery has ever been replaced since 2017? These details would help narrow down if we're looking at the same problem. If you want my advice, get the battery checked first before exploring more complex issues. The X3 and X4 are pretty similar in their electrical systems, so it might save you some headache.

Thanks for sharing that info! Just had my service last month at 141016 km and interestingly, no battery issues were flagged. The car starts perfectly fine, and all other electrical components work great, no dim lights or slow starts. Only the seats are acting weird. The strange part is that the error code specifically points to the passenger seat module. Since everything else is working normally, I'm starting to think it might be more of a seat control module issue rather than a battery problem. I'll definitely keep the battery possibility in mind though, always good to start with the simpler fixes! Did your mechanic mention anything about seat control modules when they were diagnosing your issue?

Hey again! Since you mentioned the service history and the specific error code, I should add something about my experience with the X3. While my initial problem was indeed battery-related, I actually had another seat-related issue about six months later that sounds more like what you're describing. The passenger seat control module on my X3 started acting up in a similar way, wouldn't adjust with ignition, and the memory settings were delayed. Turns out there was a faulty wiring harness under the passenger seat that was causing intermittent connection issues with the control module. It wasn't obvious at first because everything else was working fine, just like in your case. My mechanic found some corroded connectors in the wiring harness that were interrupting the signals. The repair involved replacing the harness and recalibrating the seat module. Cost me around 400 Euro, but it fixed the problem completely. Given that your error code specifically points to the passenger seat and you're not having any other electrical issues, I'd bet you're dealing with something similar. Might be worth having your mechanic check the wiring harness and connections before replacing any expensive modules. These seats have quite complex wiring, and it's a common failure point in our cars.

Thanks so much for the detailed follow-up! That wiring harness issue sounds exactly like what might be happening with my X4. Really helpful to know about the corroded connectors, makes total sense since the symptoms are so similar. I've booked an appointment with my mechanic for next week and I'll definitely mention checking the wiring harness and connections first. The price you mentioned seems reasonable for the fix, especially compared to replacing the entire module. At least now I can go in with some specific things to discuss rather than just describing the symptoms. Really appreciate you taking the time to share both your experiences. Having a clearer idea of what to expect helps a lot. I'll probably work on the car this weekend and do a visual inspection of the connectors myself before taking it in. Thanks again for the help!