Comfort unlock constantly unlocking on approach

[junta]

Hi all,

First post here: hope this forum can shed some light.

My 2014 640i GC has developed an issue whereby, as I approach from within about 5 feet the comfort unlock fires - but it fires constantly, unlocking the doors repeatedly.

At first I suspected dodgy door handles that were perhaps shorting out, but now when I sit in the car, I also get a warning on the dash saying the key isn't present. If I get the key out of my pocket and hold it up, it starts fine.

I have replaced the keyfob battery, and tried it in both fobs - same issue.

Ran the cluster diagnostics tool and found:

• The voltage whilst engine is off is 11.8v - this might be a bit low?
• Couple of error codes are listed -
• E12C01 - Env1[k 0116861, Env2[s] 332696513 - Left fuel level sensor: Short circuit to B+
• E114BC - Env1[k 0119176, Env2[s] 336847606 - Dashboard: Instrument cluster detects fault on MOST

Any ideas before I send her to an autoelectrician? Thanks in advance!

[LA640WS]

voltage is way too low! start there. I had gremlins similar to yours with comfort slow close, nav screen resets and other bad behaviours. replaced battery with 105 AGM and those things went away

[junta]

Roger that! Will investigate a new battery asap.

[swissfraser]

I had the same behaviour and you're most likely going to need a new door handle. In my case I didnt care about comfort access so avoided the issue by unplugging the sensor completely. No more door issues and no more battery drain issues. Takes 2 minutes.

[Smooth6]

Honestly I had the same exact thing going on with my 640i. My research brought me to the fact that I had a 95mh installed in it. The car requires 105mh. The dealership where I bought it from forgot to register the battery which is a big deal. But you can code the car to run off of a 95 mh. I did that and all the problems went away instantly.

[junta]

Ok, and how do we code the car to run from 95 mh? Is that something I can do from home?

[Smooth6]

I have the foxwell nt710. It's an OBD2 computer that hooks up for bmw. And through that you can register your battery to the proper size. It's pretty easy as there are options for 90 MH all the way to 105 MH.

[junta]

Originally Posted by Smooth6

I have the foxwell nt710. It's an OBD2 computer that hooks up for bmw. And through that you can register your battery to the proper size. It's pretty easy as there are options for 90 MH all the way to 105 MH.

Nice, thanks for the info. Will look into it.

[Qsilver7]

Originally Posted by junta

Ok, and how do we code the car to run from 95 mh (AH = amp hour)? Is that something I can do from home?

Depending on what software or app you have, you’ll usually see a list of AH (amp hour) selections. If your battery’s AH isn’t listed, then select the AH rating that is closest. For example, many H8/49 class size batteries can be 90AH, 92AH, or 95AH…so you would select the AH rating that is closest in the AH list in your software for the type of battery you installed. If you have the Bimmercode app…if you installed an AGM battery with an AH rating of 90/92/95 … then you would select for the 90AH AGM battery. If you were to install an aftermarket AGM 95R/H9 class size battery and it had a 100AH rating, then you would select the 105AH AGM battery since it is the closest spec listed: