It may not trip a CEL but will trip a "secondary air" code in the DME if the entire system isn't working correctly. (Which includes the pump, the valve(s), and the vacuum solenoid and vacuum lines which open the valve(s).) It is possible that it trips a CEL though as well. Either one would probably prevent you from passing smog, if you have that where you live.



I don't think your key problem is what you think it is. Re-synchronizing one key shouldn't get the other one to start working again too. I think you may have a different problem.

And remember that resynching just one key will block any/all other keys not sync'ed at the same time. :thumbup:

Mirror Switch - eBay - https://www.ebay.com/itm/154970786449

If you still have the metal arm, this is an option - https://www.access-electrical.co.uk/shop/view/-18453

This might also be an option - BMW E53 1999~2006 Door power mirror micro switch - Hong Mei Trading Co., Ltd

Yes, and OP, you can use a Foxwell or BMW Scanner (among other things) to see if each key is synchronized. As soon as you put it in the ignition it will tell you which key is in the ignition and whether it is synchronized or not. If you have one of these tools, try checking both keys. If both are still synchronized, then like wpoll said, you did not actually resynchonize the one key. Something else is going on.

Yes, on cold start up the air pump would whine. Two less expensive pumps were tried. Both set a DME code at start up. A Hella finally stopped the code.

Micro switch: BMW E53 X5 Series Door power mirror micro switch-皇泰ä¼�æ¥*社Wong Tai Co., Ltd

Thanks everyone for all the replies. I'm back with a quick update, sorry it took a bit longer:

- The secundary airpump has been disconnected for a few weeks now and there is zero downside and have been no faults. No CEL either. Of course the car throws a faultcode when scanning with software, but that's not an issue. I doubt it will be an issue with the emision over here (Netherlands), but the next general inspection for my car is only in 12 months. I can always plug it back in if need be.
- I have manually bent back the metal part of the microswitch of my driverside mirror, and so far it's kept up great. When I try to fold the mirrors it works 4/5 times. Sometimes they do nothing at all, and other times they keep unfolding automatically. But the next day it just works again. Not sure what to think of this. If it gets worse I will buy the replacement as suggested by @wpoll, thanks for the links!


Of course a new issue has come up in the meantime. On my old X5 (3.0i), the driver side door stopped working because the previous owner pulled the door handle the wrong way. This has seemingly now also started on my new 4.6is when I pulled the doorhandle while it was frozen shut. It was 6 below 0 Celcius that night. Whenever I now pull the door (even when it's not frozen), it seems to push the window a little bit as well..

I'm afraid the handle broke on the inside, again. However if I pull really hard and abrupt, the door still opens. For now, at least

I wonder if your euro market DME doesn't throw a fault code when the secondary air pump is disconnected. My USDM car certainly did while I had mine not working -- though in my case, I disconnected the vacuum line that goes to the valve.

If you can get some kind of silcone emulsion or silicone product on the door weatherstripping it will prevent the freezing. It gets worse if the skin is worn off the weatherstrip which allows it to hold moisture.

I took off the door card and even the locking mechanism, nothing seems to be broken or out of order. Here are two photos of how the door handle stays when in rested position, it's bumped up a bit. If you push it rather harsh it gets semi-flush to the door, but it moves back when you stop pushing:

https://imgur.com/a/ZxvMqWP

And here's a video from inside the door itself with a flashlight, when pulling on the door handle. Nothing seems out of ordinary:

https://youtube.com/shorts/SVDXBNsigSE

Do I have to replace that inside carrier handle again? Really not looking forward to that

The problem is most likely in the door handle/carrier. It should be fairly obviuos when you start taking it off. You are there already so not much more work. Make sure you seal up the vapour barrier nicely when you put it back together or you will have problems with the lock mechanism itself freezing.