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Discussion Starter #1
Hello gang!

Received fault code 21FA31 (2016-1000RR) - Balance-pipe valve servomotor - mechanical fault or blockage or internal electrical fault. So I know where it is located, how does one test it? The exhaust one is pretty easy to check, you can see it move when you adjust the throttle. Does the balance-pipe sevomotor work the same? It's not moving when I adjust the throttle, or it just happens at higher RPM's? Can you test with Ohms meter? Trying to figure out if I need a new one.

Thanks
Kelsey W.
 

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I am guessing it is a 15/16 model. Common issue is the bushings wear out and the play in the flapper will cause a code. The Balance Pipe is in the headers between tubes 2 and 3. The servo motor is on the left side frame rail below the fuel tank ,and above the radiator. Mine was warranty out at 3600 miles as it did the same thing in 2016.
 

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Thanks for the response BMW_388. When you turn the key on, should it move? Any way of telling if its the flapper/bushings or servo motor?
 

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When its running if the bushings are wore out, it will rattle really bad. At least mine did. Then the cable will fray on the end really bad and cause a jam of it working correctly I have seen on others. Start removing body work and look in there at it, and listen to the sound while it is running.
 

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If you disassemble the servo and remove the cables that may satisfy the ECU and negate the fault. Maybe. Yes, it should cycle when you turn on the ignition.
 

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Discussion Starter #6
Thanks guys, really appreciate the help, love forums, especially when the pandemic going on in the world!
So it doesn’t cycle when I turn it on, no weird noises, took the cable off the flapper seems to move freely, no friction. I’m thinking it’s the servomotor but I want to be certain before spending $$!
 

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If the servomotor is bad you can always replace it with a servobuddy. Or find a used servo on eBay.
 

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@ Skapan, I thought the servo buddy was for the exhaust servomotor? Under further inspection, you can hear the servomotor click, but no cable move:(
 

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you can use the servo buddy on both ends when you install a full exhaust. So if you leave the rear working and disable the front with the servo buddy is fine too
 
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