ABS sensor spacer needed?
 

So I replaced an inductive speed sensor (old style) on my front wheel carrier with a hall-effect sensor (new style). The sensor itself is fine and reads the correct currents, but it doesn't follow the 48 teeth profile of the stub axle (more like 2 pulses/ rev).

The parts diagram mentions a spacer, but no firm answer whether or when it would be needed. So I am turning to you guys :) Do late model (> 2002) 986 have a spacer on the front ABS sensors?

I checked on the diagrams that I have the correct sensor, there is only one stub axle for the whole lineup and wheel carriers should be the same. So I can just imagine this spacer....

Descripotion in here does not mention any spacer.It is not completely clear.
No need to source the spacer, why not using normal washers or other distance pieces and testing it again to ensure you really need them.

But:
If the speed sensor has been removed or replaced due to an ABS fault, a traction control fault, or as part of post-accident repairs, a functional test must be carried out using the Porsche System Tester 2 – via the ‘Actual Values’ menu, ‘Speed’ submenu.

And:
The optimum air gap (the distance between the sensor tip and the ABS ring) in these systems is typically between approximately 0.5 mm and a maximum of 1.5 mm.

Plus what I found:
The aluminium wheel hubs on early 996 models, in particular, are extremely prone to oxidation around the ABS sensor mounting. The corroded aluminium pushes the sensor up slightly (increasing the gap). Garages then tend to scrape the bore clean. If too much material is removed in the process, or if the factory-fitted spacer is omitted, the new sensor will sit too low

Thanks. I measured the gap which is about 0.5mm on one side and 0.6mm on the other. I loosened the screw holding it to the wheel carrier and it pushed itself out a bit (due to the bend in the wires). This didn't really change anything.

Also I blew it clean with compressed air as I figured there might be parts of the old sensor stuck between the teeth (not really visible though). Some rust and dust blew out, but no change.

As you might imagine, I am a bit puzzled now. I will swap left and right sensor (as the right wasn't working at all) to at least rule out a wiring issue and check whether the right side would detect normally.

To be continued..