Thread: FL2 Haldex pump electrical "noise" on stereo and aftermarket head unit

Hello All,

I have an 09 FL2 i6. I recently installed an aftermarket GPS, reverse, screen, etc in the centre cubby hole. All works well but......There is a high pitched noise present in this unit and the aux input to the existing factory stereo every time a pump on the rear diff runs. This pump attached to the Haldex coupler runs for two seconds approximately every eight seconds when the engine is running.

My question is: Is this normal? The pump noise can easily be heard with the engine running listening underneath the boot space.

I am fairly confident I can filter out this noise and have a few things to try to accomplish this. Just would be handy to know if this is normal function of the Haldex pre charge pump, etc.

Thanks guys, Fitzie

Turns out this is normal operation of the pre charge pump on gen 4 Haldex.