M Performance Carbon Package disables Hands free trunk release

[BajanM3]

I'm not sure if this is in the U.S also or not...but for sure, it applies to Canada.

If you order the M Performance Carbon Package (which comes with the carbon fiber rear diffuser) - this add on will disable the Hands Free Trunk Release which is part of the Comfort Access System.

I have a 2017 M3 with M Performance Carbon Package, and I found out AFTER I received my vehicle that this feature is disabled.

At first, I didn't understand why. So I took my car in, and they did a deep dive.

[First ]- they looked to see if the module and sensor were there for this feature. And they are.

There are two sensors (black strips ) right below the rear bumper. One runs at the top...one at the bottom.

The top one senses your foot moving forward (this is the input signal)...the bottom one senses your foot moving away (this is the output signal)

These two sensors are connected to a module right beside them with 3 wires(power, ground and LIN communication)

[Second ]- they reprogrammed my car just to make sure that it wasn't missed being programmed the first time

[Third ]- it STILL didn't work. So they contacted BMW Canada.

And the answer they got was - this feature was disabled when the vehicle arrived at the port in Canada and the Carbon Fiber diffuser and my Performance exhaust was installed.

Apparently it arrived at the port from Germany with the feature enabled...but at the port, when they programmed the car after installing the diffuser - the code was removed

The dealership is NOT given this code. If they had it - then they would be able to reprogram it and enable this feature.

The reason the tech was given ...was that the diffuser has three slots(or grooves) that stick out further. So when you try to kick, your shin may hit them first. Also - the sensor may or may not detect your foot sometimes because your foot may not be going underneath far enough.

Also - the diffuser may crack/break when trying to kick at it multiple times to get it to work.

So since it won't work correctly consistently, and to avoid owners bringing their car in for a feature that works sometimes, and not others...they decided to disable it all together.

I just wish they would've told me this when I was ordering my car.

Would I of changed my mind...HELLL NOO!! The rear diffuser looks friggin sweet man with the titanium performance exhaust.

But...I would've liked to known so I wouldn't have to go through all of this to find out why.

I have attached pictures. #4 on the image is the rear diffuser, and you can see in the description that it says the feature has been disabled.

The other image is an email from BMW to my service Tech.

Just thought I'd let others know who may be looking for a solution to this problem in the future.

[banff]

Carbon fiber can act as a Faraday cage and block signals making things like kick trunks not work.

[SD ///M4]

This is not news. It has been known since the CF Rear Diffuser has been available.

Try searching and you'll find many discussions of this and workarounds that people have discovered that will allow the hands-free option to work. Most of them are not in this subforum.

[obardain]

Have a look at these threads.

http://f80.bimmerpost.com/forums/sho....php?t=1030977

http://f80.bimmerpost.com/forums/sho....php?t=1083083

http://www.bimmerpost.com/goodiesfor...ectronics1.pdf
Page 35 explains the operation of the comfort access.

[Arcades]

Yeah this isn't really new.

Carbon Fiber blocks the signals given out by the trunk sensor. When you install the MP rear diffuser, they should tell you and warn you that this is going to happen. A dealership would normally tell you ahead of time that this is going to happen.

Most CF diffusers would do this unless the diffuser itself doesn't completely cover the sensor, in which case it would open, depending on the diffuser itself.

[Mistertmac]

Bleh, CF > Kick feature. I never used that feature, it used to use itself, leaving my trunk wide open when I walked away. CF is much more sexy.....

[BajanM3]

Originally Posted by SD ///M4

This is not news. It has been known since the CF Rear Diffuser has been available.

Try searching and you'll find many discussions of this and workarounds that people have discovered that will allow the hands-free option to work. Most of them are not in this subforum.

Thanks.
I'm new around here.
I tried searching..but I find that the search function doesn't work that well. There's SOOO much info in these forums...I find it hard to find what I'm looking for.

[FatHulk]

Originally Posted by BajanM3

Thanks.
I'm new around here.
I tried searching..but I find that the search function doesn't work that well. There's SOOO much info in these forums...I find it hard to find what I'm looking for.

Same New owner and did a search for this and ended up on another forum but wasn't conclusive. Hoping this was coded out on my car.