AFM Ohm Reading

[drola]

i took aoart the afm of a 3.2 to make a new contact path for the arm.
does anyone know the resistance readings i should be looking for once I do this?
i'm reading it between the 2 center pins which seem to be the ones for the arm since it fluctuates as i move it
thanks

[HaroldMHedge]

The Bentley manual only says that terminals 2 and 3 should have resistance and it should change without interruption. You are testing the correct terminals.

I could not find a resistance value in the Porsche manual but it does discuss voltage changes. With the ignition on and AFM wiring connected, you need to check terminal 2 (second from left). With the AFM vane closed it should read approx. 0.26V and fully open approx. 4.6V.

[FrankM_]

Hi,

Just did the same last weekend as I had a serious discontinuity at Idle (unable to get anywhere between 1000rpm and 2400 rpm. Checked it with my small scope and yes, it jumped around. When I opened up the AFM, the track was worn rigth to the PCB board in that area.
Retracked, and checks out fine now on my scope. Unfortunately, due to the CORONA lockdown, unable to testdrive at the moment.

You should measure between pin 6 (GND) and pin 7 (Uout), but you should not measure resistance. Put a battery or a regulated power supply between pin 6 and pin 9 (Uin). I used a regulated 5V (4.96-4.99 here) and you push the flap through its paces. You should see a smooth increment (on an analog voltmeter or a scope).
You can find my readings below. It is the % of Uout/Uin that matters.

[FrankM_]

Sorry, my readings didn't come through in the previous post.

[Flat Six]

Very helpful; thanks, Frank

[drola]

Yes very helpful. Thanks for that