Author Topic: 21FA21 Exhaust Flap Servo Motor Adjustment Error  (Read 623 times)

Riverfurm

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21FA21 Exhaust Flap Servo Motor Adjustment Error
« on: December 08, 2016, 01:06:55 PM »
Installed an Akrapovic full system. Since the exhaust flap valve was removed and the exhaust flap servo motor was kept. I get a 21FA21 exhaust servo motor adjustment error code in the ecu when doing a full system scan. It does not turn on the check engine light (I have not taken it on a long ride yet). Is this normal?

I sent an Email to Akrapovic help desk and this is the reply I got.....

Thank you for your interest in Akrapovic Exhaust Systems. No codes should come up if the system was properly installed. You must follow our installation manual EXACTLY to avoid any errors. If you are having an issue, please reach out to your local BMW dealer for additional support.

It seems to my there would be no way it would not set an error code. Servo motor moving but nothing is happening.

I sent them an email back....

With the removal of the exhaust valve the servo has nothing to operated any more. No more exhaust flap valve, no limit on the cables when the valve stop when fully open and closed. I referred to the shop manual and there is an adjustment for the valve.That is why the cable are adjustable. Called the selling BMW dealer and they stated that with the valve removed the servo motor has no stops and it will set a code. The code it is setting is 21FA21 "Exhaust Flap Servo Motor Adjustment Error" That would make sense since there is no adjustment. It does not turn the check engine light on in the instrument cluster. I followed the instruction, including the part of removing the servo motor cables and reinstalling it. Have you done a complete scan of the bikes that had this system installed?
At this point the only solution is to install an electronic device such as a Servo Buddy that will fool the system that there is still a exhaust flap in the exhaust system. But that is another $59.00. That should've been included in the exhaust kit. Or a warning that this issue can occur. Here's a link that explain how removing the exhaust flapper valve on a BMW motorcycle will set code 21FA21. http://www.skutr.net/bmw-exhaust-servo-motors/

So any help with the extra $59 I will have to spend on a Servo Buddy kit? (not holding my breath)

Anyone run into this issue when removing the exhaust flap valve?

Thanks.
16 S1000XR  Commuter
12 K1600GTL 2up Sport Tour
 11 Aprilia 750 Dorosduro (Traded)
 05 F650GS (Sold)
 02 K1200RS First BMW (sold)
 00 Kawasaki 1100 ZRX (sold)
 83 Suzuki 750 GS (sold)
 Riverfurm along the Delaware River

Jughead

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Re: 21FA21 Exhaust Flap Servo Motor Adjustment Error
« Reply #1 on: December 19, 2016, 03:36:36 PM »
There is a bit of a Heath Robinson way of sorting it.

Use 2 electrical connector blocks.  Remove the metal part from the plastic, undo the screws and fit these to the 2 cables at their respective limits.

All that is required is tension on the cable that would simulate an open and a closed flap.

Then re calibrate the servo motor and it will relearn where the stops you installed on the cables are.

Riverfurm

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Re: 21FA21 Exhaust Flap Servo Motor Adjustment Error
« Reply #2 on: December 20, 2016, 12:31:05 AM »
Does the GS911 do a servo motor relearn?
16 S1000XR  Commuter
12 K1600GTL 2up Sport Tour
 11 Aprilia 750 Dorosduro (Traded)
 05 F650GS (Sold)
 02 K1200RS First BMW (sold)
 00 Kawasaki 1100 ZRX (sold)
 83 Suzuki 750 GS (sold)
 Riverfurm along the Delaware River

Jughead

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Re: 21FA21 Exhaust Flap Servo Motor Adjustment Error
« Reply #3 on: December 20, 2016, 09:40:34 AM »
Does the GS911 do a servo motor relearn?

Yes it does.

Riverfurm

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Re: 21FA21 Exhaust Flap Servo Motor Adjustment Error
« Reply #4 on: December 20, 2016, 11:18:50 AM »
Thanks for the information :)
16 S1000XR  Commuter
12 K1600GTL 2up Sport Tour
 11 Aprilia 750 Dorosduro (Traded)
 05 F650GS (Sold)
 02 K1200RS First BMW (sold)
 00 Kawasaki 1100 ZRX (sold)
 83 Suzuki 750 GS (sold)
 Riverfurm along the Delaware River

Riverfurm

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Re: 21FA21 Exhaust Flap Servo Motor Adjustment Error
« Reply #5 on: January 09, 2017, 03:43:17 PM »
Had to get a servo buddy from Skutrnet.  https://www.woodcraft-cfm.com/cgi-bin/commerce.cgi?search=action&category=SKSB   The first one I installed set a different code. They had a revised version that they sent me. No codes but I have not done a road test yet due to snow.
16 S1000XR  Commuter
12 K1600GTL 2up Sport Tour
 11 Aprilia 750 Dorosduro (Traded)
 05 F650GS (Sold)
 02 K1200RS First BMW (sold)
 00 Kawasaki 1100 ZRX (sold)
 83 Suzuki 750 GS (sold)
 Riverfurm along the Delaware River

Riverfurm

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Re: 21FA21 Exhaust Flap Servo Motor Adjustment Error
« Reply #6 on: February 03, 2017, 12:43:16 AM »
So everything seems to work fine now with the updated servo buddy.  Akrapovic still says that I did something wrong with the install. But they have not tested the exhaust system on a 2016 US version. They are not very helpful.
16 S1000XR  Commuter
12 K1600GTL 2up Sport Tour
 11 Aprilia 750 Dorosduro (Traded)
 05 F650GS (Sold)
 02 K1200RS First BMW (sold)
 00 Kawasaki 1100 ZRX (sold)
 83 Suzuki 750 GS (sold)
 Riverfurm along the Delaware River