[bazald]

I drive a 2008 335xi. It's had its fair share of issues over the past few years, but I don't think I have the full story on what occurred a few days ago.

I was driving in fairly extreme cold in Michigan thanks to the polar vortex, and it felt like there was higher vibration and lower engine output than usual. After driving for no more than a couple of minutes, I encountered an AWD and DSC error like in a previous thread. My local BMW dealer claims that the only problems are a low pressure sensor that I've ignored (on their previous advice) and some worn out spark plugs needing replacement. I have two open questions about this situation.

1. I hear that limp mode should restrict the vehicle to first (and possibly second) gear, but my gas pedal didn't have any effect on my speed at all. I was restricted to a stuttering 2 MPH as a result. Has anyone encountered this level of limp mode before? Is it fully explained by the malfunctioning parts they've listed? Would it matter if I was in sport mode or normal mode?

2. When I later started the car back up, the check engine light was off and the date and time needed to be reset. It was cold and I was handing the vehicle off to be towed, so I didn't have time to check if everything had been reset or if it was selective in some way. The check engine light had been on for the preceding year thanks to the faulty low pressure sensor. Is this kind of reset normal after limp mode? Is it indicative of another problem, such as with the battery? And if the battery is involved, why was I able to start the vehicle?

Thanks for reading and for any possible understanding you can impart.