Your specialist subject..the life and times of comfort access

[B21]

Comfort access is a number of additional capablities added to E89s in addition to the normal key fob things.

The technologies and parts were widely used on a number of other BMW cars..but rarely fitted to the E89.

The only two obvious ways to see if you have comfort access (apart from a VIN check) is to see if each door pull has 3 raised ridges moulded into the handle AND if the fobs have a removeable non rechargeable battery CR2032..these two features define comfort access.

So what does comfort access do, if its working properly?

You can raise the roof on the fob..not possible with the standard system

You can unlock and lock the car by touching the 3 moulded lines with the fob in your pocket

You can start the car without inserting the fob into the 'slot'

Not earth shattering.

However it turns out its not a very reliable system, either on E89s or elsewhere.

The most common failure is the electronics in the door handle (quite complex with a microprocessor) fail..often resulting in an unexplained current drain warning / manin battery going flat if left..

Also remote operation of roof/windows/locks all start to go wrong in various ways..

In my case a red herring of current drain that I associated with the fittingof the ID4Cluster was my downfall..

The roof wouldn't open on the fob, a high current drain was shown on iDrive ..

I fitted a new battery..tried various things with matters getting worse..

I then noticed that when I touched the driver door handle with the car parked and cold that it was warm to the touch.

I've used a thermal camera to show the image and temperatures..nealry 50c on the driver door and 25c on the passenger door..with the rest of the car at 16c..

Its an expensive problem to fix..each door handle is one unit at £500..

I bought a second user one for £100 with view to replace..but needs painting and that process potentially damages the ability of the door handle to 'sense' touch..

Current (pun) plan is to remove the door handle and simply disconnect the lead that provides power and gets data from the handle.

There's a second connector for the extended lighting which I'll leave plugged in..

 

[matsmith749]

Small edit - 5 raised ridges.

 

[B21]

So it took about 10 mins to remove the driver door handle..disconnected the power/data feed..current dropped from 360ma to 200ma..

Driver door now stone cold…

It took 5 hours to get the pax door handle off..what a bitch..disconnected that..current now at 76 ma…within the 80ma DM`e current violation threshold…at £500 to fix a handle, given their reliability I’ll pass ..

 

[Mr Tidy]

That just looks like another gimmick I'd never want that will result in big bills once the warranty has expired, much like electric handbrakes!

Although I had a rear door lock fail on my 3 Series last year that resulted in the central locking fuse failing so every door stayed open all the time, apart from the driver's one that stayed permanently locked.

Diagnosis and fix at RBM came to £491.94 on a Cat N Shed that WBAC value at just over £800. :roll:

It's electronics that will kill older cars now instead of rust!

 

[B21]

That just looks like another gimmick I'd never want that will result in big bills once the warranty has expired, much like electric handbrakes!

Although I had a rear door lock fail on my 3 Series last year that resulted in the central locking fuse failing so every door stayed open all the time, apart from the driver's one that stayed permanently locked.

Diagnosis and fix at RBM came to £491.94 on a Cat N Shed that WBAC value at just over £800. :roll:

It's electronics that will kill older cars now instead of rust!

Yes comfort access ranks alongside smart phone unlocking etc..obviously when you buy a second hand car it is what it is in terms of options..Internet shows many many BMWs with this failure mode.. :thumbsdown:

Actually I like electronic parking brakes but we can discuss that at another time..

 

[kashp]

Hi, and sorry for resurrecting and old thread. I seem to have exactly the same issue. Looking at disconnecting only the drivers door and leaving the passenger door handle connected. Will this cause any issues?

 

[B21]

Hi, and sorry for resurrecting and old thread. I seem to have exactly the same issue. Looking at disconnecting only the drivers door and leaving the passenger door handle connected. Will this cause any issues?

That should be fine…usually they go bad more or less together..personally I’d just take both off line

 

[kashp]

Thanks for the insight. If I code out comfort access would I need to put the key in the slot to start or would keyless start continue to work?

 

[B21]

No coding required…keyless start still works plus roof closing on the fob…key in slot still works